just to let you guys know, i think i will be a quad owner by mid year :D . just cant get enough of teh goodness.

You will need to go to bass rehab...

OK, now we are getting somewhere. If you are going to continue using the Velodyne (which was not clear to me in the beginning), then you need to gain-match the two subs. This will ensure that they are playing at the same level so that the trim setting in the AVR drives both subs equally. Here is an outline of the gain-matching procedure:

1. Pick a spot in the center of your room away from the walls.
2. Move the first sub to that spot, and connect the audio and power cables.
3. Place the SPL meter immediately in front of the sub's cone, at a distance of 1-2 inches, centered on the cone.
4. Mark the position of the sub (using masking tape is a good way).
5. Run the sub channel level-setting tone from the AVR and adjust the sub's gain to the desired level (I use 90 dB).
6. Being very careful not to disturb the SPL meter's position, remove the first sub and replace it with the second sub. Make sure it is lined up exactly as the first sub with respect to the SPL.
7. Running the AVR test tone, adjust the second sub's gain to match the first sub's (90 dB).
8. Place the two subs back in the position you want them to be.
9. Run Audyssey room correction (a critical step, IMO, otherwise you aren't correcting for room issues).
10. Observe what trim level Audyssey sets in the AVR. Ideally, it should be in the -3 to +3 dB range. If it is too far towards either limit, go back to step 5 and use either a lower or higher target gain level, depending on your final results.

By using this procedure, you will ensure that both subs are outputting at the same level. Want to give it a try? (Obviously I like typing more than HTG...)

Ha ha Jerry, You're just better at cut and pasting. :p

just to let you guys know, i think i will be a quad owner by mid year :D . just cant get enough of teh goodness.

I have told you this before Kimwyn.

Before you even think of a Quad system you either need to upgrade your main speakers or buy MBMs. In your room you would just be wasting money unless you take my advice and improve on achieving better mid-bass response.

I definitely understand what you are saying but i just simply crave more and more bass it has nothing to do with anything i feel is lacking.....since the AS-EQ1, i dont think i am really lacking anything, it sounds quite fine to me but i just want more.

I definitely understand what you are saying but i just simply crave more and more bass it has nothing to do with anything i feel is lacking.....since the AS-EQ1, i dont think i am really lacking anything, it sounds quite fine to me but i just want more.

but, but, but, you're not getting it man. There is more in midbass. :D More than you think. Are you crossing over your subs in 100hz range?

My DD is crossed at 100Hz.

but, but, but, you're not getting it man. There is more in midbass. :D More than you think. Are you crossing over your subs in 100hz range?

What subs do you have and what mains are you using?

My DD is crossed at 100Hz.

Are you aware that 90hz is the LPF on them? You're making your subs work harder rather than letting them do what they do best.

What subs do you have and what mains are you using?

My mains are Jamo's C-807s and a pair of HSU VTF-15H's

I've heard those Jamos before and unfortunately i didnt like them too much. I will change my crossover to 80Hz and see if there is a difference but i love it as it is right now.

Question, if i change my crossover, do i need to re-run EQ1?

Are you aware that 90hz is the LPF on them? You're making your subs work harder rather than letting them do what they do best.

Sorry Jim, but the ULS-15, per Pete's conversation with me, claims they can play much higher frequencies. Are you sure about the LPF on the ULS?

Sorry Jim, but the ULS-15, per Pete's conversation with me, claims they can play much higher frequencies. Are you sure about the LPF on the ULS?

Al, that's what I understand if i'm reading the site correctly, is the lowpass defeatable?

I've heard those Jamos before and unfortunately i didnt like them too much. I will change my crossover to 80Hz and see if there is a difference but i love it as it is right now.

Question, if i change my crossover, do i need to re-run EQ1?

I would man. You may like it better,,, or not lol.

imho, there isn't any point in have your sub do what your mains already do.

I feel the same way about horn tweeters. (personal taste):D

Question, if i change my crossover, do i need to re-run EQ1?

No. The AS-EQ1 calibration is completely independent of any crossover setting on the AVR.

I would man. You may like it better,,, or not lol.

imho, there isn't any point in have your sub do what your mains already do.

I feel the same way about horn tweeters. (personal taste):D

You would change your mine if you heard my Klipsch legacy speakers with new third party X-overs installed. :D

Al, that's what I understand if i'm reading the site correctly, is the lowpass defeatable?

You are missing reading it. That is if you use the built-in sub xover. But if you toggle off the xover on the sub and use the AVR bass management then they are capable of higher frequencies.

You would change your mine if you heard my Klipsch legacy speakers with new third party X-overs installed. :D

Pretty nice I assume? :)



You are missing reading it. That is if you use the built-in sub xover. But if you toggle off the xover on the sub and use the AVR bass management then they are capable of higher frequencies.

Ok, Al thanks for clearing that up for me.

Pretty nice I assume? :)

Ok, Al thanks for clearing that up for me.

http://www.runemasterstudios.com/graemlins/images/2thumbs.gif

http://www.runemasterstudios.com/graemlins/images/2thumbs.gif

AL I have not heard you make any detailed differences between the dual and triple drive. I was actually waiting all this time to hear what you think. So.......??????

Also, have you ever heard a Submersive HP? What is the SQ difference?

Also, have you ever heard a Submersive HP? What is the SQ difference?

I'd be interested in this too. I got to hear a pair of SubM's at the KC meet a couple of weeks ago and I rated them highest of the group. A quad drive is similar in price, with some added placement flexibility. The Hsu's are the only sub left that I am considering, but haven't been able to hear or get a comparison to the SubM's from someone who's heard both. Preferable apples to apples dual drive to one SubM or quad drive to dual SubMs.

In a small sealed room there may not be too much difference between the ULS:Submersive in a 2:1 ratio other than more smoothing with duals since output wouldn't be an issue but I'd venture a guess that a Submersive HP has more output and better mid-upper bass than dual ULS'. Plus you NEVER hear about a Submersive bottoming out.

Nothing against ULS', multiples in a sealed room where output and bottoming out aren't concerns would perform extremely well.
Tim
Edit: If you're comparing dual Submersives to quad ULS' I'd take the Seatons any day. But if it were one Submersive to 2 ULS' then it becomes harder since you only have one source with the single Submersive whereas the ULS' give the advantages multiples give you with bigger sweet spot easier frequency smoothing. That may make up for a little less output/midbass.

AL I have not heard you make any detailed differences between the dual and triple drive. I was actually waiting all this time to hear what you think. So.......??????

Also, have you ever heard a Submersive HP? What is the SQ difference?

He is some impressions I have already posted.

We watched Star Trek 09 a couple of days ago. We have seen it at least 4 times and every time they went into warp drive my wife jumped. The third uls-15 created such a concussion hit it was really cool. :cool: I have never felt that before.

The 3rd ULS biggest improvement is either when I play the system at lower volume the bass is still omni present and then of course when I am listening to a movie near reference the shock and awe that happens when the subs need to knock it up a notch is jawdropping.

I have not heard a SubM HP yet.

Bottom line the more subs you add the less each one has to work to give you the same amount of bass with the added ability to easily handed the high dynamic peaks better. I had 2 12" and 2 15" before so swapping one 12" with the 15" is not as a dramatic difference as you would think. I do have an increase in output below 20Hz then I did before so that is a plus. Is there something that I have not addressed that you have a question about?

In a small sealed room there may not be too much difference between the ULS:Submersive in a 2:1 ratio other than more smoothing with duals since output wouldn't be an issue but I'd venture a guess that a Submersive HP has more output and better mid-upper bass than dual ULS'. Plus you NEVER hear about a Submersive bottoming out.

Nothing against ULS', multiples in a sealed room where output and bottoming out aren't concerns would perform extremely well.
Tim
Edit: If you're comparing dual Submersives to quad ULS' I'd take the Seatons any day. But if it were one Submersive to 2 ULS' then it becomes harder since you only have one source with the single Submersive whereas the ULS' give the advantages multiples give you with bigger sweet spot easier frequency smoothing. That may make up for a little less output/midbass.

If the uls-15 is correctly setup it does not bottom out. Mine have never had an issue even when I only had the dual drive and they are not in a sealed room. I am glad you are enjoying your SubM. I too am impressed by the SubMs but both choices are viable options.

Edit: If you're comparing dual Submersives to quad ULS' I'd take the Seatons any day. But if it were one Submersive to 2 ULS' then it becomes harder since you only have one source with the single Submersive whereas the ULS' give the advantages multiples give you with bigger sweet spot easier frequency smoothing. That may make up for a little less output/midbass.

Thanks, this helps. It would be quads, in my case. Room is about 2200 cu.ft. and sealed, if that changes any impressions.

Can the ULS actually bottom out? I've never heard mine do that. I thought they used an underhung driver? Isn't it impossible to bottom out a underhung driver?

Thanks, this helps. It would be quads, in my case. Room is about 2200 cu.ft. and sealed, if that changes any impressions.

In that space a Quad drive or dual Submersives will both kick a$$. Whichever way you go you'll be happy. For you it may come down which is easier, placing 4 smaller subs or 2 larger ones.

Shady and HTG,
I don't know if it's bottoming out or not I'm just going by owners on this thread occasionally describing brief funky noises during intense demand.

AL I have not heard you make any detailed differences between the dual and triple drive.


To add to what HTG has already reported, the addition of a third ULS-15 to my listening room improved the smoothness of the bass reaponse noticeably. I have attached before and after 8-position REQ measurements (1/12 smoothing, with Audyssey correction).

The increased smoothness contributes to the overall quality of the bass, which is what I was looking for. I am not concerned about volume, only quality. Having said that, I haven't experienced "bottoming out" on my subs. I think that some people might confuse clipping with bottoming out, and it isn't that difficult to get an amp to go into clipping, regardless of the sub.

^^
Wow, the third one really took care of those dips pretty well.

And I agree quality trumps quantity. I rarely get to fully utilize the output of my HP's.
Tim

quick question, is it a good idea to keep the ulf trim all the way at 16kz and let audysee xt or xt32 take care of smoothing the frequecies OR should i raise the ulf so I can get possible higher volume.

quick question, is it a good idea to keep the ulf trim all the way at 16kz and let audysee xt or xt32 take care of smoothing the frequecies OR should i raise the ulf so I can get possible higher volume.

The best way to do it with Audyssey.... is to set the ULF trim to 50Hz....run the auto calibration...then turn the ULF trim back down to 16 Hz if you have a large room.

The best way to do it with Audyssey.... is to set the ULF trim to 50Hz....run the auto calibration...then turn the ULF trim back down to 16 Hz if you have a large room.

HTG, I have struggled with the ULF trim, i.e. I can't tell what it is doing. Can you briefly explain what you hear when you select different settings for this control?

For lack of knowing better, I set the dial at 12 o'clock (approx 35 Hz) before running Audyssey, and don't change it after the calibration has finished. Do you select 50 Hz based on your experience, or is this a recommendation from someone else?

HTG, I have struggled with the ULF trim, i.e. I can't tell what it is doing. Can you briefly explain what you hear when you select different settings for this control?

For lack of knowing better, I set the dial at 12 o'clock (approx 35 Hz) before running Audyssey, and don't change it after the calibration has finished. Do you select 50 Hz based on your experience, or is this a recommendation from someone else?An earlier post (http://www.avsforum.com/avs-vb/showpost.php?p=20549410&postcount=1672) in this thread offers good info.

An earlier post (http://www.avsforum.com/avs-vb/showpost.php?p=20549410&postcount=1672) in this thread offers good info.

Thanks for reminding me of this posting, Roger. Even after re-reading it, I wasn't satisfied with my understanding about how the ULF trim setting might affect my system. So, I set up my REW kit and took some measurements. The results are attached.

I took only one measurement for each of three ULF trim settings (16 Hz, 35 Hz, and 50 Hz), all at the MLP at ear height using an RS SPL. While the graph clearly shows the slight differences among the three settings, I am unable to tell the difference in my casual listening tests.

However, I still believe that the ULF trim setting should be set before running Audyssey, and not adjusted after the calibration has completed. This way, we can ensure that Audyssey takes into consideration any differences that the trim setting makes.

Are those even differences??? Those appear so slight......

Are those even differences??? Those appear so slight......

Well yes, that's my point. Evidently small enough that my ears can't tell the difference. I don't think obsessing over the ULF trim setting is time well spent.

Thanks for reminding me of this posting, Roger. Even after re-reading it, I wasn't satisfied with my understanding about how the ULF trim setting might affect my system. So, I set up my REW kit and took some measurements. The results are attached.

That jibes with what I measured. About 7dB difference at 15Hz between the lowest and highest settings. Not a huge difference.

Still a difference though.
And a cool feature. If I had a dual or quad drive in a sealed room (or any room for that matter) I would run Audyssey with the ULF trim @ 50 then switch to 16 hz afterward for a slightly rising response down low. Maybe do that for movies and you could always just adjust ULF trim back to 50 for music if you wanted to tighten it up a bit.
I do something similar with my Submersive HP's. I run Audyssey in the 19 hz DSP program (1) then switch to DSP program 2 (15hz). This gives a slightly rising response down low for movies, I put it back to 19 hz DSP mode for multichannel music. Works great.
I think the ULF trim can probably create more of a rising response this way than my DSP modes if the space is sufficiently small and sealed.
Tim

Thanks for reminding me of this posting, Roger. Even after re-reading it, I wasn't satisfied with my understanding about how the ULF trim setting might affect my system. So, I set up my REW kit and took some measurements. The results are attached.

I took only one measurement for each of three ULF trim settings (16 Hz, 35 Hz, and 50 Hz), all at the MLP at ear height using an RS SPL. While the graph clearly shows the slight differences among the three settings, I am unable to tell the difference in my casual listening tests.

However, I still believe that the ULF trim setting should be set before running Audyssey, and not adjusted after the calibration has completed. This way, we can ensure that Audyssey takes into consideration any differences that the trim setting makes.

Remember that 6 db is a doubling of subwoofers. The differences at 30hz on your graph would be insignificant, <20hz that is significant. To compare you would have to be a/bing material with lots of low content.

As capecodorthopod suggests this would be great for tailoring flat vs. rising response. As well as driver control for someone pushing the driver to its linear limits.

Remember that 6 db is a doubling of subwoofers. The differences at 30hz on your graph would be insignificant, <20hz that is significant. To compare you would have to be a/bing material with lots of low content.

As capecodorthopod suggests this would be great for tailoring flat vs. rising response. As well as driver control for someone pushing the driver to its linear limits.

I'm sure you are correct. However, for my type of listening, which is mostly music and satellite TV, the amount of sub-20 Hz content is minimal. I used the graphs to select what looks like the flattest overall response (35 Hz), and am unlikely to adjust the trim for different types of content. I have three ULS-15's, so changing the trims would be a PITA.

I'm sure you are correct. However, for my type of listening, which is mostly music and satellite TV, the amount of sub-20 Hz content is minimal. I used the graphs to select what looks like the flattest overall response (35 Hz), and am unlikely to adjust the trim for different types of content. I have three ULS-15's, so changing the trims would be a PITA.

The response looks great! Thanks for posting your findings.

Thanks for the reply everyone. i may set mine possibly around 30hz for now.
Austin your graphs dont change much (yeah 10db is alot but i was expecting the traditional "rolloff" curve") but i bet its because of you having multiple subs working together. My room is about 3000cuft and i have only one sub. My low end may roll off more than yours. I also currently only have audysee 2eq as well. I cant wait till I get a better receiver.

I received my ULS-15 last week. It replaced a 10 year mirage bps-150.
Wow, I am very pleased. I have been missing out on a lot of sound.

I planned on trying the wireless today.
I am using a pioneer sc-55 with no bass management, but it sounds pretty good in my room.

I purchased the VTF-2 MK4 for myself and while it's a great sub, I sort of wish I'd gone for the ULS-15. It's a pretty big jump price-wise, though.

Glad you guys are liking yours!

Thanks for reminding me of this posting, Roger. Even after re-reading it, I wasn't satisfied with my understanding about how the ULF trim setting might affect my system. So, I set up my REW kit and took some measurements. The results are attached.

I took only one measurement for each of three ULF trim settings (16 Hz, 35 Hz, and 50 Hz), all at the MLP at ear height using an RS SPL. While the graph clearly shows the slight differences among the three settings, I am unable to tell the difference in my casual listening tests.

However, I still believe that the ULF trim setting should be set before running Audyssey, and not adjusted after the calibration has completed. This way, we can ensure that Audyssey takes into consideration any differences that the trim setting makes.

There is almost a 6db increase at 20hz on the graph you posted. That is not what I would consider a slight difference. Since this difference can affect how Audyssey calculates what filters it wants to apply after calibration it sometimes gets it wrong and adds even more boost down low causing the amp on the sub to clip. Therefore after I had a conversation with Pete about some ppl having issues with clipping, we both came to a conclusion, it would be better to recommend ppl set the ULF trim to 50hz prior to running Audyssey then changing the ulf trim back down to the 16Hz post calibration.

I'm sure you are correct. However, for my type of listening, which is mostly music and satellite TV, the amount of sub-20 Hz content is minimal. I used the graphs to select what looks like the flattest overall response (35 Hz), and am unlikely to adjust the trim for different types of content. I have three ULS-15's, so changing the trims would be a PITA.

I guess we have different listening habits. You say you do mostly music and satellite tv? :confused: You don't use your system to watch Bluray discs which are capable of outputing lower Hz then broadcast TV? Also I listen to a variety of music. To fully enjoy the capabilities of the ULS-15 some of the music I listen to is Organ music, electronica and the lowest of low material... stuff like Dubstep and torture tests stuff like what is produced by Bass Mekanik. I heard a song yesterday by Beat Dominator called Night Bass. This song has strong stuff below 15Hz in it. :eek: This is why I have my ULF trim set to 16Hz.

Both of our methods are viable options in setting up the ULS-15s depending on how you plan on using the subs. Thanks for sharing the graphs Jerry.

I received my ULS-15 last week. It replaced a 10 year mirage bps-150.
Wow, I am very pleased. I have been missing out on a lot of sound.

I planned on trying the wireless today.
I am using a pioneer sc-55 with no bass management, but it sounds pretty good in my room.

Welcome to the club gamecock.

There is almost a 6db increase at 20hz on the graph you posted. That is not what I would consider a slight difference. Since this difference can affect how Audyssey calculates what filters it wants to apply after calibration it sometimes gets it wrong and adds even more boost down low causing the amp on the sub to clip. Therefore after I had a conversation with Pete about some ppl having issues with clipping, we both came to a conclusion, it would be better to recommend ppl set the ULF trim to 50hz prior to running Audyssey then changing the ulf trim back down to the 16Hz post calibration.

I guess we have different listening habits. You say you do mostly music and satellite tv? :confused: You don't use your system to watch Bluray discs which are capable of outputing lower Hz then broadcast TV? Also I listen to a variety of music. To fully enjoy the capabilities of the ULS-15 some of the music I listen to is Organ music, electronica and the lowest of low material... stuff like Dubstep and torture tests stuff like what is produced by Bass Mekanik. I heard a song yesterday by Beat Dominator called Night Bass. This song has strong stuff below 15Hz in it. :eek: This is why I have my ULF trim set to 16Hz.

Both of our methods are viable options in setting up the ULS-15s depending on how you plan on using the subs. Thanks for sharing the graphs Jerry.

There has been a lengthy discussion over on the Audyssey thread about how in certain situations Audyssey can over-boost bass response below a sub's 3 dB cutoff (which I suspect is fairly low for the ULS-15). If this is a problem, then your approach of setting the ULF trim at 50 Hz prior to calibrating might make good sense. Sometimes these answers are not obvious, and it takes a lot of experimenting to get it right!

As for my listening tastes, I do listen to Blu-ray movies, but this accounts for probably only 10% of my listening time. And I have never been one to listen to something just to hear wall-shaking bass, although when it does happen I get a smile on my face... :)

There has been a lengthy discussion over on the Audyssey thread about how in certain situations Audyssey can over-boost bass response below a sub's 3 dB cutoff (which I suspect is fairly low for the ULS-15). If this is a problem, then your approach of setting the ULF trim at 50 Hz prior to calibrating might make good sense. Sometimes these answers are not obvious, and it takes a lot of experimenting to get it right!

As for my listening tastes, I do listen to Blu-ray movies, but this accounts for probably only 10% of my listening time. And I have never been one to listen to something just to hear wall-shaking bass, although when it does happen I get a smile on my face... :)

I just like to :) a lot. :cool:

There is almost a 6db increase at 20hz on the graph you posted. That is not what I would consider a slight difference. Since this difference can affect how Audyssey calculates what filters it wants to apply after calibration it sometimes gets it wrong and adds even more boost down low causing the amp on the sub to clip. Therefore after I had a conversation with Pete about some ppl having issues with clipping, we both came to a conclusion, it would be better to recommend ppl set the ULF trim to 50hz prior to running Audyssey then changing the ulf trim back down to the 16Hz post calibration.

I personally experienced this when I initially got my ULS and used it with MultXT. Its even worse with dynamic volume engaged, which really boosts the subsonic range. Thankfully HTG talked me through it.

An increase of 6db takes 4 times the power. The low end needs the most power to reproduce. So it can be easy to get into trouble with large boost on the bottom end. I would guess that the amp in the sub is already being taxed at high volume levels at the low boost setting.

So my ULS got the cops called on me. I fell asleep with the media room going, it kept on repeating the the menu track, and the bass could be heard by my neighbors.

Everyone is probably like, "So?"

I live in a single family house where the distance between the media room and the other person's bedroom was a good 30-40 yards, through two insulated brick structures. I have no windows in the media room either.

Oops :)

So my ULS got the cops called on me. I fell asleep with the media room going, it kept on repeating the the menu track, and the bass could be heard by my neighbors.

Everyone is probably like, "So?"

I live in a single family house where the distance between the media room and the other person's bedroom was a good 30-40 yards, through two insulated brick structures. I have no windows in the media room either.

Oops :)

Your neighbor must have very sensitive ears! :D

So my ULS got the cops called on me. I fell asleep with the media room going, it kept on repeating the the menu track, and the bass could be heard by my neighbors.

Everyone is probably like, "So?"

I live in a single family house where the distance between the media room and the other person's bedroom was a good 30-40 yards, through two insulated brick structures. I have no windows in the media room either.

Oops :)

How in the world did the cops wake you if you were able to sleep through that much bass...

This is a funny story..

How in the world did the cops wake you if you were able to sleep through that much bass...

This is a funny story..

They didn't wake me. I had two missed calls and a voicemail on my cell phone from the police department. I went to apologize to my neighbor the next morning and they proceeded to tell me how he was knocking on glass, kicking the front door, etc.

Apparently I have a citation in the mail...that is this not so funny part.

They didn't wake me. I had two missed calls and a voicemail on my cell phone from the police department. I went to apologize to my neighbor the next morning and they proceeded to tell me how he was knocking on glass, kicking the front door, etc.

Apparently I have a citation in the mail...that is this not so funny part.

Ouch. Perhaps HSU can name their next subwoofer "The Citation"..

They didn't wake me. I had two missed calls and a voicemail on my cell phone from the police department. I went to apologize to my neighbor the next morning and they proceeded to tell me how he was knocking on glass, kicking the front door, etc.

Apparently I have a citation in the mail...that is this not so funny part.

Don't they have to measure dB in order to legally cite you?

Don't they have to measure dB in order to legally cite you?

You prove it and I'll use it. The neighbors felt bad because they were actually just worried about us. Needless to say, I felt bad for waking up their baby and then keeping the mom from going back to sleep (they both could hear it)

Your neighbor must have very sensitive ears! :D

Wow first time you have ever posted here I believe.

Hello Dr. P.S. Hsu. So glad you have started posting again. Congrats on winning multiple awards on all of your designs.

Wow first time you have ever posted here I believe.

Hello Dr. P.S. Hsu. So glad you have started posting again. Congrats on winning multiple awards on all of your designs.

Same here and well deserved.

Wow first time you have ever posted here I believe.

Hello Dr. P.S. Hsu. So glad you have started posting again. Congrats on winning multiple awards on all of your designs.

Thank you guys. My daughter has gone to college, so now I have more time to have fun .. :D

Congratulation on kicking your kid out of the house. :p Just Kidding kind Sir. Let's not have too much fun now....you have more subs to design. :) :D :cool:

Edit: Tell Pete I said Hi. I have not seen him around for awhile. :(

Congratulation on kicking your kid out of the house. :p Just Kidding kind Sir. Let's not have too much fun now....you have more subs to design. :) :D :cool:

Edit: Tell Pete I said Hi. I have not seen him around for awhile. :(

She is having a ball of a time at MIT. :)

She is having a ball of a time at MIT. :)

Just like Dad huh? What is she studying, if I may ask?

Just like Dad huh? What is she studying, if I may ask?

NOT like Dad. She is studying Biological Engineering.

NOT like Dad. She is studying Biological Engineering.

Impressive. I hope she excels at it like you did in your line of study. http://www.runemasterstudios.com/graemlins/images/crossfingers.gif

So Dr? I really do enjoy the ULS-15s for their effortless ability in reaching the lower octaves but you know us obsessed bass fanatics always crave more. And your VTF15H was a homerun for you but what else are you thinking of creating? Any hints on what you might be cooking up next? :D

Impressive. I hope she excels at it like you did in your line of study. http://www.runemasterstudios.com/graemlins/images/crossfingers.gif

So Dr? I really do enjoy the ULS-15s for their effortless ability in reaching the lower octaves but you know us obsessed bass fanatics always crave more. And your VTF15H was a homerun for you but what else are you thinking of creating? Any hints on what you might be cooking up next? :D

Sorry. I will use Apple's model and stay mum till the product is ready to launch! :D

Sorry. I will use Apple's model and stay mum till the product is ready to launch! :D

Really, You can tell me. It would just be between you and me. ;) :p
It was a pleasure to finally speak to you and I hope to see you around more often. http://www.runemasterstudios.com/graemlins/images/cool_shades.gif

Really, You can tell me. It would just be between you and me. ;) :p
It was a pleasure to finally speak to you and I hope to see you around more often. http://www.runemasterstudios.com/graemlins/images/cool_shades.gif

I will be around more often from now on... :)

It's funny how it took Dr.Hsu's daughter to go off to university to get this thread moving again.....thanks Dr.Hsu for allowing her to go so our thread could bump again :D

On a serious note though, congrats on all the accolades which your products have received as IMO, they are (at least the ULS is) very good items.

It's funny how it took Dr.Hsu's daughter to go off to university to get this thread moving again.....thanks Dr.Hsu for allowing her to go so our thread could bump again :D

On a serious note though, congrats on all the accolades which your products have received as IMO, they are (at least the ULS is) very good items.

Thank you. Thank you very much. We will continue to bring interesting and good products to the market... :)

Thank you. Thank you very much. We will continue to bring interesting and good products to the market... :)

I think you meant to type great products.

I think you meant to type great products.

Ha Ha Ha. Super duper products :D

She is having a ball of a time at MIT. :)

Maybe when she finishes her degree you two could whip up a new biological subwoofer that personalized sound based on our genetic makeup....just a thought.

Congrats Dr. Hsu on all you success's and thanks for all your contributions to the audio industry.

Maybe when she finishes her degree you two could whip up a new biological subwoofer that personalized sound based on our genetic makeup....just a thought.

Congrats Pete on all you success's and thanks for all your contributions to the audio industry.

brad

Maybe when she finishes her degree you two could whip up a new biologically subwoofer that personalized sound based on our genetic makeup....just a thought.

Congrats Pete on all you success's and thanks for all your contributions to the audio industry.

She will invent something that would hook up to one's nerves that will allow one to perceive DC to 1 GHz with no distortion at up to 180 dB without damaging one's ears... :D

BTW, I am Dr. Hsu, not Pete... :)

She will invent something that would hook up to one's nerves that will allow one to perceive DC to 1 GHz with no distortion at up to 180 dB without damaging one's ears... :D

BTW, I am Dr. Hsu, not Pete... :)

My apologies...I have corrected the name.

Sounds like the the Orbit Shifter that I described to my wife as being tuned in outer space and puts out 200 db's at 10hz from 1 mile away. Her reply was priceless... "How much does the damn thing cost?"

dr.hsu, i always wanted to know, when you guys had announced that there was a new subwoofer on the horizon (which turned out to be the 15H) there were many speculations on what it could be. I, for one, was saying it could have been a ULS-18.....:eek: In your mind, what are your opinions on HSU releasing an 18 incher and dual opposed 15s or anything along those lines that could compete in SPL and low distortion with the likes of a paradigm sub2 or seaton submersive?

dr.hsu, i always wanted to know, when you guys had announced that there was a new subwoofer on the horizon (which turned out to be the 15H) there were many speculations on what it could be. I, for one, was saying it could have been a ULS-18.....:eek: In your mind, what are your opinions on HSU releasing an 18 incher and dual opposed 15s or anything along those lines that could compete in SPL and low distortion with the likes of a paradigm sub2 or seaton submersive?

Ah, Good Try! :D

hey guys, now that i have the AS EQ1 i was wondering, what do you guys think of me putting the subs directly behind my LP, amps facing each other and EQing from there? Please note that the subs would be in the middle of the room, but 7ft away from the back wall which means 14 ft from the front wall.

No i do not have any measuring tools and would not be able to know what the FR looks like. Its just a question that i wanted to see what the general response was.

hey guys, now that i have the AS EQ1 i was wondering, what do you guys think of me putting the subs directly behind my LP, amps facing each other and EQing from there? Please note that the subs would be in the middle of the room, but 7ft away from the back wall which means 14 ft from the front wall.

No i do not have any measuring tools and would not be able to know what the FR looks like. Its just a question that i wanted to see what the general response was.

Hi Kimwyn,

Best part of this hobby.... Tweaking right? Can't hurt to try. If it does not sound better you can always go back to the way you had them. :D

Thanks Al, but if i have them firing away from each other do i have to adjust the phase?

hey guys, now that i have the AS EQ1 i was wondering, what do you guys think of me putting the subs directly behind my LP, amps facing each other and EQing from there? Please note that the subs would be in the middle of the room, but 7ft away from the back wall which means 14 ft from the front wall.

No i do not have any measuring tools and would not be able to know what the FR looks like. Its just a question that i wanted to see what the general response was.

My experience has been that you can use the graphs that the AS EQ 1 generates to come up with some great results in positioning.:)

Thanks Al, but if i have them firing away from each other do i have to adjust the phase?

Your AS EQ 1 should take care of any phase issues, I believe the directions have you set your sub(s) on 0 and it adjusts from there.

thanks bz, but i read that the graphs produced by the EQ1 do not show some of the nulls and peaks as with REW. Is this really true?

thanks bz, but i read that the graphs produced by the EQ1 do not show some of the nulls and peaks as with REW. Is this really true?

sort of. The graph from the EQ1 is smoothed by the software. In practice this is ok because you shouldn't be correcting for very narrow nulls and peaks anyway because these narrow anomolies change rapidly when you move your head a few inches. In REW, you can measure without smoothing and you can see every little spike/dip

hey guys, now that i have the AS EQ1 i was wondering, what do you guys think of me putting the subs directly behind my LP, amps facing each other and EQing from there? Please note that the subs would be in the middle of the room, but 7ft away from the back wall which means 14 ft from the front wall.

No i do not have any measuring tools and would not be able to know what the FR looks like. Its just a question that i wanted to see what the general response was.

It would be useful if you reported your experience with the AS-EQ1 to date, since we haven't heard from you for quite some time. Where are the subs placed right now? If you are thinking about moving them, are you unhappy with how they sound now? What is it you are trying to accomplish?

As mentioned earlier, the "before" graph can be useful in evaluating placement options. True, it is approx 1/6 smoothing, but the graph is still a good tool.

thanks bz, but i read that the graphs produced by the EQ1 do not show some of the nulls and peaks as with REW. Is this really true?

sort of. The graph from the EQ1 is smoothed by the software. In practice this is ok because you shouldn't be correcting for very narrow nulls and peaks anyway because these narrow anomolies change rapidly when you move your head a few inches. In REW, you can measure without smoothing and you can see every little spike/dip

Hi Kimwyn,
Like warpdrive is saying, the AS EQ 1 graphs should give you a good enough representation of your sub positioning. You can then work from there to find what is most pleasing to you.
I probably produced 40-50 graphs with my AS EQ 1 & ULS DD when I had them. I checked distances as close as 1/2 foot in both directions (once I found a good position)to see changes in the graphs as well as raising the subs 4". I started with a minimum of 3 mic positions and worked up from there. The results were great.
Good luck with your quest!
BZ

hey guys, now that i have the AS EQ1 i was wondering, what do you guys think of me putting the subs directly behind my LP, amps facing each other and EQing from there? Please note that the subs would be in the middle of the room, but 7ft away from the back wall which means 14 ft from the front wall.

No i do not have any measuring tools and would not be able to know what the FR looks like. Its just a question that i wanted to see what the general response was.

With the subs 14 ft from the front wall, you will get a dip centered around 20 Hz (a 20 Hz positive wave reflected off the front wall will arrive back just when the sub is producing a negative wave, cancelling each other). An MBM behind you and a true sub or true subs up front might work better for this layout. Of course the equalizer can flatten the response, but having to boost 20 Hz will put a big strain on the system.:D

It would be useful if you reported your experience with the AS-EQ1 to date, since we haven't heard from you for quite some time. Where are the subs placed right now? If you are thinking about moving them, are you unhappy with how they sound now? What is it you are trying to accomplish?

As mentioned earlier, the "before" graph can be useful in evaluating placement options. True, it is approx 1/6 smoothing, but the graph is still a good tool.

The subs are placed up front right now between the center and the left and right channels. Since I have had the EQ1 the bass has been a lot smoother. Very detailed and added just a bit more punch. From my constant reading of various threads on this board, I figured some nearfield placement could do well in achieving some more visceral impact and punch. So that's why I am asking. My system is mainly for movies and not much music. Although I listen to music, it's not critical listening. I do not sit in one spot and listen either. Heck, the music I listen to doesn't even deserve to be critically listened to anyway, so that is not very important. The most important thing for my system is impact, punch and shake. And that is what I am trying to achieve.

With the subs 14 ft from the front wall, you will get a dip centered around 20 Hz (a 20 Hz positive wave reflected off the front wall will arrive back just when the sub is producing a negative wave, cancelling each other). An MBM behind you and a true sub or true subs up front might work better for this layout. Of course the equalizer can flatten the response, but having to boost 20 Hz will put a big strain on the system.:D

Thanks dr.HSU for the advice but I am still a bit hesitant on adding MBMs to my system. Would another ULS directly behind me help me in achieving my goal stated above?

The subs are placed up front right now between the center and the left and right channels. Since I have had the EQ1 the bass has been a lot smoother. Very detailed and added just a bit more punch. From my constant reading of various threads on this board, I figured some nearfield placement could do well in achieving some more visceral impact and punch. So that's why I am asking. My system is mainly for movies and not much music. Although I listen to music, it's not critical listening. I do not sit in one spot and listen either. Heck, the music I listen to doesn't even deserve to be critically listened to anyway, so that is not very important. The most important thing for my system is impact, punch and shake. And that is what I am trying to achieve.

Two ULS-15s? As I said, based purely on the length of your room, placing the subs behind the listening position will make 20 Hz weak. The EQ1 can flatten that out, but headroom at 20 Hz would be low. Best if you can add a MBM behind the LP with the ULS-15s still up front. Crossover at 50 Hz between the MBM and the ULS. That way, you have high headroom across all frequencies.

Post a detailed sketch of your room [including adjoining room(s) if these are linked via usually open doorways.] Maybe other dimensions will compensate for the dip at 20 Hz. If so, behind the LP may be great without having to get a MBM. You basically want high headroom at most frequencies even after EQ.

Adding an MBM introduces a complexity with the AS-EQ1. How does the MBM receive the audio signal from the AVR? Does it connect to one of the two sub out connections? If this is the case, then there would be two equalized subs and one not-equalized MBM. Not sure how this would sound.

If the two front subs are equidistant from the MLP, then they could be driven off of one sub channel on the AS-EQ1 (connected with a Y-cable), and the MBM could be on the other sub out channel. This way, everything would be equalized. However, I don't know anyone who has done this, or whether it would work.

I mean no disrespect, but adding an MBM to a system that relies on Audyssey room correction adds what I see as unnecessary complexity. When I wanted more bass, I added a third ULS-15, with quite good results.

Adding an MBM introduces a complexity with the AS-EQ1. How does the MBM receive the audio signal from the AVR? Does it connect to one of the two sub out connections? If this is the case, then there would be two equalized subs and one not-equalized MBM. Not sure how this would sound.

If the two front subs are equidistant from the MLP, then they could be driven off of one sub channel on the AS-EQ1 (connected with a Y-cable), and the MBM could be on the other sub out channel. This way, everything would be equalized. However, I don't know anyone who has done this, or whether it would work.

I mean no disrespect, but adding an MBM to a system that relies on Audyssey room correction adds what I see as unnecessary complexity. When I wanted more bass, I added a third ULS-15, with quite good results.

My suggestion would be to feed the MBM and the two ULS the same signal from the EQ1. The MBM and the ULS is effectively a bi-amped system. Set the crossover on the ULS to 'in', 50 Hz. Set the MBM crossover to 'out'. That way, the ULS handles 50 Hz down while the MBM handles 50 Hz up (up to the crossover set by the processor). The EQ1 will equalize all the frequencies handled by the ULS and the MBM. Just as the Audyssey will equalize the woofer and tweeter in a loudspeaker, think of the MBM+ULS as a 'speaker' with two 15" woofer and a 12" mid-woofer. This is a bit like the Velodyne 1812. In that case, you have an 18" woofer for low bass crossed over to a 12" mid woofer. Here you have two 15" woofers for low bass and a 12" for mid-bass. If you really want to time align them, you can add a delay to the MBM.

My suggestion would be to feed the MBM and the two ULS the same signal from the EQ1. The MBM and the ULS is effectively a bi-amped system. Set the crossover on the ULS to 'in', 50 Hz. Set the MBM crossover to 'out'. That way, the ULS handles 50 Hz down while the MBM handles 50 Hz up (up to the crossover set by the processor). The EQ1 will equalize all the frequencies handled by the ULS and the MBM. Just as the Audyssey will equalize the woofer and tweeter in a loudspeaker, think of the MBM+ULS as a 'speaker' with two 15" woofer and a 12" mid-woofer. This is a bit like the Velodyne 1812. In that case, you have an 18" woofer for low bass crossed over to a 12" mid woofer. Here you have two 15" woofers for low bass and a 12" for mid-bass. If you really want to time align them, you can add a delay to the MBM.

Thank you for the kind and informative response, Dr. Hsu. I have several follow-up questions, please. I have attached a rough drawing of my listening room, as well as REW frequency response measurements of the current set-up (Note: crossover to main speakers is set to 80 Hz).

Where would you recommend that I place the MBM?

The recommended connection is using a Y-cable to one of the subs. Would you use the sub in the rear of the room for this connection?

The MBM User Guide says "You may purchase some digital delay box to time align the MBM-12 MK2 to the true subwoofer". Do you have a part number for such a delay box, or a web link?

AJ, do you use the EQ1 with the 3 ULSs? do those graphs represent an EQed response?

My suggestion would be to feed the MBM and the two ULS the same signal from the EQ1. The MBM and the ULS is effectively a bi-amped system. Set the crossover on the ULS to 'in', 50 Hz. Set the MBM crossover to 'out'. That way, the ULS handles 50 Hz down while the MBM handles 50 Hz up (up to the crossover set by the processor). The EQ1 will equalize all the frequencies handled by the ULS and the MBM. Just as the Audyssey will equalize the woofer and tweeter in a loudspeaker, think of the MBM+ULS as a 'speaker' with two 15" woofer and a 12" mid-woofer. This is a bit like the Velodyne 1812. In that case, you have an 18" woofer for low bass crossed over to a 12" mid woofer. Here you have two 15" woofers for low bass and a 12" for mid-bass. If you really want to time align them, you can add a delay to the MBM.

I think it is me but i dont understand what is said here? Feed the MBM and the TWO ULSs the same signal?????? what signal??? do you mean put them on the same output? If so, even if the ULSs are equidistant, the MBM surely is not. How would the EQ pick up that the MBM is not the same distance if it is one the same output as the ULSs?

Thank you for the kind and informative response, Dr. Hsu. I have several follow-up questions, please. I have attached a rough drawing of my listening room, as well as REW frequency response measurements of the current set-up (Note: crossover to main speakers is set to 80 Hz).

Where would you recommend that I place the MBM?

The recommended connection is using a Y-cable to one of the subs. Would you use the sub in the rear of the room for this connection?

The MBM User Guide says "You may purchase some digital delay box to time align the MBM-12 MK2 to the true subwoofer". Do you have a part number for such a delay box, or a web link?

If it was me Jerry I would have all three ULSs farfield and have the single MBM where your third uls-15 presently is. I use an old bass reflex Velodyne to give me the same effect as an MBM but when it dies I have plans to replace it with a MBM instead of going after the fourth ULS.

If Kimwyn remembers I suggested last year sometime that he would either benefit moving to larger floor standing speakers with woofers larger then what he presently owns or he too should go the MBM route. It was a pleasent suprise that Dr. Hsu confirmed my idea. :)

If it was me Jerry I would have all three ULSs farfield and have the single MBM where your third uls-15 presently is. I use an old bass reflex Velodyne to give me the same effect as an MBM but when it dies I have plans to replace it with a MBM instead of going after the fourth ULS.

If Kimwyn remembers I suggested last year sometime that he would either benefit moving to larger floor standing speakers with woofers larger then what he presently owns or he too should go the MBM route. It was a pleasent suprise that Dr. Hsu confirmed my idea. :)

i know you have mentioned this but i am very wary about adding the MBMs. what would i be accomplishing by adding an MBM nearfield that IS SIMILAR to changing to larger floorstanders which IS DIFFERENT to adding a third ULS? Do you get what i just asked??? :D

i know you have mentioned this but i am very wary about adding the MBMs. what would i be accomplishing by adding an MBM nearfield that IS SIMILAR to changing to larger floorstanders which IS DIFFERENT to adding a third ULS? Do you get what i just asked??? :D

Yes I understand. The ULS-15 is a true subwoofer with it strenghts being 50HZ and down below 16HZ. Larger woofers in floor standers can move more air easier then smaller woofers so they are able to give the kick in the chest you are looking for. The MBM essentially does this the same way. If you put all three subs on the same output from the EQ the mic will pick up the three subs as a single sub and will then adjust the distance accordingly so that all three subs are in phase with the main L/R speakers in your setup.

Am I making sense?

This is the reason why my system sounds so good to everyone who hears it including ppl who have more expensive systems then mine. I have 12" woofers and 15" passives in my floor stand speakers and I have the additional Velo nearfield.

Yes I understand. The ULS-15 is a true subwoofer with it strenghts being 50HZ and down below 16HZ. Larger woofers in floor standers can move more air easier then smaller woofers so they are able to give the kick in the chest you are looking for. The MBM essentially does this the same way. If you put all three subs on the same output from the EQ the mic will pick up the three subs as a single sub and will then adjust the distance accordingly so that all three subs are in phase with the main L/R speakers in your setup.

Am I making sense?

This is the reason why my system sounds so good to everyone who hears it including ppl who have more expensive systems then mine. I have 12" woofers and 15" passives in my floor stand speakers and I have the additional Velo nearfield.

Ok, i think i get you :o but on the point of the EQ, if the 3 subs are not equidistant from the LP i think that creates a problem. Am i right Jerry? cause i can be wrong for damn sure........

AJ, do you use the EQ1 with the 3 ULSs? do those graphs represent an EQed response?

I use an AVR with Audyssey MultEQ XT32, which has sub equalization equivalent to the AS-EQ1. The two front subs are equidistant from the MLP, and are on sub channel 1. The third sub is on sub channel 2. This configuration allows Audyssey to time-delay all three subs correctly. The graphs represent the overall equalized bass response at the MLP, which includes the three subs as well as my left and right main speakers (which are tower speakers each with three 6.5 inch bass drivers). Response is with Dynamic EQ off.

If it was me Jerry I would have all three ULSs farfield and have the single MBM where your third uls-15 presently is. I use an old bass reflex Velodyne to give me the same effect as an MBM but when it dies I have plans to replace it with a MBM instead of going after the fourth ULS.

If Kimwyn remembers I suggested last year sometime that he would either benefit moving to larger floor standing speakers with woofers larger then what he presently owns or he too should go the MBM route. It was a pleasent suprise that Dr. Hsu confirmed my idea. :)

You saw my response curve, which I think is pretty good. Do you think the MBM would make it that much better?

Ok, i think i get you :o but on the point of the EQ, if the 3 subs are not equidistant from the LP i think that creates a problem. Am i right Jerry? cause i can be wrong for damn sure........

I do not have an EQ....All four subs are not equal distance from the LP. the Velo is at 1 foot, one ULS is 2 feet away, third uls is 13 feet away and the fourth is 14 feet away. They are all on one output. I had to measure multiple times before I got the correct distance setting in the AVR so all bass sounds like it is coming from the floor speakers. IOW the distance setting was set correctly in order that there is not a dip in FR at the x-over point of 80Hz. This is exactly what your EQ will do. It does not matter where the subs are located. What matters is when the lower frequencies are measured by the mic and then the EQ will adjust them accordingly.

You saw my response curve, which I think is pretty good. Do you think the MBM would make it that much better?

Your response curve is awesome looking. I'm getting a liitle up in age, so forgive my memory, but what speakers do you have in your system?

If you put all three subs on the same output from the EQ the mic will pick up the three subs as a single sub and will then adjust the distance accordingly so that all three subs are in phase with the main L/R speakers in your setup.

Am I making sense?



No disrespect, HTG, but this doesn't sound right to me. Just because you place three sub's on the same channel, and if the subs are at different distances from the MLP, they cannot be time-aligned correctly by Audyssey.

Your response curve is awesome looking. I'm getting a liitle up in age, so forgive my memory, but what speakers do you have in your system?

I have PSB Synchrony One's across the front.

^^^^thats what i was thinking but i know AL is a lot more knowledgeable than i am so i wanted to know about it.

I do not have an EQ....All four subs are not equal distance from the LP. the Velo is at 1 foot, one ULS is 2 feet away, third uls is 13 feet away and the fourth is 14 feet away. They are all on one output. I had to measure multiple times before I got the correct distance setting in the AVR so all bass sounds like it is coming from the floor speakers. IOW the distance setting was set correctly in order that there is not a dip in FR at the x-over point of 80Hz. This is exactly what your EQ will do. It does not matter where the subs are located. What matters is when the lower frequencies are measured by the mic and then the EQ will adjust them accordingly.

I understand what you are saying. If you conduct measurements and adjust delays to achieve the smoothest transition at the crossover point, this is an acceptable approach used by many. I don't doubt that your system sounds great. Even with my equalization, I use REW to tweak the distance settings after calibration to achieve an even flatter response at the crossover.

If I have learned anything about bass response, it is that there are different approaches, all with merit. In the final analysis, it's whether we like what we hear! And getting there is what makes our hobby enjoyable.

not me, i hate tweaking......REW is a pain in the ass :eek: and these damn subs are too heavy :D

No disrespect, HTG, but this doesn't sound right to me. Just because you place three sub's on the same channel, and if the subs are at different distances from the MLP, they cannot be time-aligned correctly by Audyssey.

But they can be time-aligned on one output just takes a little extra effort. How many years did I do this before sub EQs or AVRs had multiple outputs. ;) The Velodyne SMS-1 does it this way. Plus if you are interested I know John Craig at one time was using just 1 output for his three asymmetrically places SubMs on his XT32 AVR. Read this (http://www.avsforum.com/avs-vb/showthread.php?p=19446901#post19446901) if you have some time.

You young whippersnappers are getting lazy with all the work being done by technology. :p

Thank you for the kind and informative response, Dr. Hsu. I have several follow-up questions, please. I have attached a rough drawing of my listening room, as well as REW frequency response measurements of the current set-up (Note: crossover to main speakers is set to 80 Hz).

Where would you recommend that I place the MBM?

The recommended connection is using a Y-cable to one of the subs. Would you use the sub in the rear of the room for this connection?

The MBM User Guide says "You may purchase some digital delay box to time align the MBM-12 MK2 to the true subwoofer". Do you have a part number for such a delay box, or a web link?

You are most welcome. You have 3 ULS! Can you sketch in the room dimensions of the adjoining rooms? Also, those REW curves - are these without EQ? If they are after EQ, please show the before EQ curves.

I think it is me but i dont understand what is said here? Feed the MBM and the TWO ULSs the same signal?????? what signal??? do you mean put them on the same output? If so, even if the ULSs are equidistant, the MBM surely is not. How would the EQ pick up that the MBM is not the same distance if it is one the same output as the ULSs?

Yes, feed the ULSs and the MBM from the output of the AS1. The ULSs up front would be about half a wavelength away at the 50 Hz crossover between the ULSs and the MBM. Try setting the ULS phase to 180 and they may integrate better. If you want to really dial it in, you can add a digital delay for the MBMs.

I am not familiar with the abilities of the AS1. If you hook a subwoofer that is set to reproduce only 50 Hz and lower to one of its output, and another that only reproduce 50 Hz and up to the other, will it try to equalize both for flat response from 20 Hz to 100 Hz? If it does that, then my suggestion above is the only way to do it.

If you can tell the AS1 that the sub connected to output 1 should only get 50 Hz and below and the sub connected to output 2 is only for 50 Hz and up, then you can connect the MBM to output 2 and the ULSs to output 1.

If it was me Jerry I would have all three ULSs farfield and have the single MBM where your third uls-15 presently is. I use an old bass reflex Velodyne to give me the same effect as an MBM but when it dies I have plans to replace it with a MBM instead of going after the fourth ULS.

If Kimwyn remembers I suggested last year sometime that he would either benefit moving to larger floor standing speakers with woofers larger then what he presently owns or he too should go the MBM route. It was a pleasent suprise that Dr. Hsu confirmed my idea. :)

I tend to agree with hometheatergeek - place the 3 ULSs up front and the single MBM at the back. I personally like the mid bass to be reproduced close to me - the direct to reflected sound ratio is higher, and you have extremely high headroom due to the close proximity to the MBM, not to mention the high SPL capability of the MBM (even when not nearfield).

You saw my response curve, which I think is pretty good. Do you think the MBM would make it that much better?

Are those curves with or without EQ? If they are with EQ, they do not tell me much. The AS EQ1 may be boosting a lot at some frequencies to get the system to be flat. If that is the case, if adding the MBM reduces somewhat the EQ needed, then adding the MBM will help a lot in making your system play louder cleaner.

No disrespect, HTG, but this doesn't sound right to me. Just because you place three sub's on the same channel, and if the subs are at different distances from the MLP, they cannot be time-aligned correctly by Audyssey.

I think Audyssey will take the effective acoustic center of the three. It will not time align each individual sub to the listener's position. It will just try to flatten any response deviation due to the phase differences between the subs.

You are most welcome. You have 3 ULS! Can you sketch in the room dimensions of the adjoining rooms? Also, those REW curves - are these without EQ? If they are after EQ, please show the before EQ curves.

I have attached a graph showing the bass response without EQ, and with EQ. I don't see any significant boosting in the displayed frequency range.

There are really no "adjoining rooms". The listening room is open in the back to the entire rest of the ground floor, approximately 1,000 square feet.

So, here is the question: assume for a moment that I have no space elsewhere in my room to place the third ULS-15. My two choices are:

1. Leave things the way they are, or
2. Replace the ULS-15 with an MBM (perhaps move the ULS-15 to the bedroom).

Is the sonic capability of the MBM such that option 2 would result in better sound?

I have attached a graph showing the bass response without EQ, and with EQ. I don't see any significant boosting in the displayed frequency range.

There are really no "adjoining rooms". The listening room is open in the back to the entire rest of the ground floor, approximately 1,000 square feet.

So, here is the question: assume for a moment that I have no space elsewhere in my room to place the third ULS-15. My two choices are:

1. Leave things the way they are, or
2. Replace the ULS-15 with an MBM (perhaps move the ULS-15 to the bedroom).

Is the sonic capability of the MBM such that option 2 would result in better sound?

What the EQ has done is to effectively boost low bass by up to 10 dB relative to the mid bass (50 - 70 Hz). i.e., if the sub level is set so the mid bass is balanced with the main speakers, then deep bass is nearly 10 dB higher than without EQ.

Can you take a response measurement of each of the ULS individually? Is it feasible to stack the ULSs on top of each other? If you can find a front location that has an unequalized response that has the strongest low bass, put all the ULSs there.

BTW, did you carefully match the outputs of all three ULSs?

For everyone and anyone who usually assist me, attached is a detailed plan of my room.

Dr.Hsu, please tell me what you think its best for my current situation and what you propose i can do to add to the "WOW" factor (e.g placing a ULS behind me or 2 MBMs or even one MBM).

For everyone and anyone who usually assist me, attached is a detailed plan of my room.

Dr.Hsu, please tell me what you think its best for my current situation and what you propose i can do to add to the "WOW" factor (e.g placing a ULS behind me or 2 MBMs or even one MBM).

I would try one MBM directly behind your sweet spot. Set the crossovers on the ULSs to 50 Hz, crossover in. Set the crossover on the MBM to out. Proceed as follows when you get the MBM:

1. Place the MBM directly behind your sweet spot. Set it's crossover to 'out', volume at half a tick up from minimum. Connect the MBM to the output of the AS EQ1 (same output as what is driving the two ULSs). Leave the MBM off.

2. Play programs you are very familiar with that has mid bass and low bass though your system. Get a good fresh memory of the balance between mid range, mid bass and low bass.

3. Turn on the MBM. Set the crossovers on the ULSs to 50 Hz, crossover 'in'. Now listen to the same program material you just played. Adjust the MBM volume till you get about the same level of mid bass.

4. Play the 50 Hz track on the CD we provided (not too loud!). If you can, sit in the sweet spot and have someone flip the phase switch on the MBM between 0 and 180. The phase that gives you stronger 50 Hz is the phase you want to leave it in.

5. Disengage the AS EQ1. Listen to the same program material and adjust the MBM level to get as close to the balance you had with just the ULSs and AS EQ1 engaged. (This would minimize how much EQ the AS EQ1 has to do).

6. Engage the AS EQ1 and let it re-equalize the new system.

The overall balance should be similar to just the ULSs, but you should have a bit tighter mid bass (the near-field placement gives you more direct sound which is always tighter), and a lot more headroom (You not only have the extremely high SPL in the mid-bass thanks to near-field placement and high output of the MBM, you also have more low bass from the ULSs because the amps in the ULSs now do not have to allocate some of it's power for mid-bass reproduction)

I didn't receive a reply from Hsu techsupport to my March 4 email query regarding a ~9 year old STF-2 that blew its fuse. Hope that the experts on this forum (Dr. Hsu?) could provide me with some advice.

When the SW stopped working there was the faint smell of burnt electronics from its port. I tried replacing the blown fuse with 250 V 2.5 A replacements, but two consecutively blew instantly.

What are my options at this time? Would it be more cost effective to pick up a new SW or to ship this to Hsu - assuming that it can be fixed. What would the repair and shipping (from SF) approximately cost? Thanks!

What the EQ has done is to effectively boost low bass by up to 10 dB relative to the mid bass (50 - 70 Hz). i.e., if the sub level is set so the mid bass is balanced with the main speakers, then deep bass is nearly 10 dB higher than without EQ.

Can you take a response measurement of each of the ULS individually? Is it feasible to stack the ULSs on top of each other? If you can find a front location that has an unequalized response that has the strongest low bass, put all the ULSs there.

BTW, did you carefully match the outputs of all three ULSs?

In the graph I provided, the blue line is without EQ, so applying EQ reduced the bass, not increased it.

And yes, I carefully followed the accepted procedure for gain-balancing the ULS-15's (the procedure recommended by Pete). I consider this a critical step in the setup process.

I didn't receive a reply from Hsu techsupport to my March 4 email query regarding a ~9 year old STF-2 that blew its fuse. Hope that the experts on this forum (Dr. Hsu?) could provide me with some advice.

When the SW stopped working there was the faint smell of burnt electronics from its port. I tried replacing the blown fuse with 250 V 2.5 A replacements, but two consecutively blew instantly.

What are my options at this time? Would it be more cost effective to pick up a new SW or to ship this to Hsu - assuming that it can be fixed. What would the repair and shipping (from SF) approximately cost? Thanks!

There are two options we recommend:
1. Upgrade to a new sub. Since you are a loyal customer, and has a non-functioning Hsu sub, we extend to you a better-than-Black Friday pricing for your upgrade. Let us know which model you want and we will let you know what price we can give you.

2. Get a replacement amp. A replacement amp is $175 plus $20 S/H.

BTW, I checked and saw that your email was sent out at 1:03 pm Sunday and we sent out a reply at 1:26 pm, 23 minutes later. Perhaps your spam blocker blocked the reply. Not many companies would respond on a Sunday let alone within 30 minutes.. :)

In the graph I provided, the blue line is without EQ, so applying EQ reduced the bass, not increased it.

And yes, I carefully followed the accepted procedure for gain-balancing the ULS-15's (the procedure recommended by Pete). I consider this a critical step in the setup process.

I understand that the blue curve is the unequalized curve. What I was pointing out is, the blue curve will sound about 5 dB louder than the red curve - 50 Hz up the blue curve averages about 5 dB higher than the red curve (just eyeballing - not a precise statement!:D). If you set the system with the blue curve to play at the same perceived loudness level, the blue curve should be about 5 dB lower. If you adjust the blue curve 5 dB lower, then the blue curve's bass below 50 Hz is down about 5 dB compared to the red curve. Hence the EQ effectively boosted low bass by 5 dB. i.e., when the system is playing at about the same perceived loudness level, with EQ engaged, 20 Hz will be about 5 dB louder.

Not many companies would respond on a Sunday let alone within 30 minutes.. :)

Agreed! Thank you for renewing my faith in your tech support. And it was indeed designated as spam, and I am unable to open it for some reason. I have pm'd you my response to your kind offer.

The AS EQ1 may be boosting a lot at some frequencies to get the system to be flat. If that is the case, if adding the MBM reduces somewhat the EQ needed, then adding the MBM will help a lot in making your system play louder cleaner.

It took me a little time to understand what you mean when you say that the low frequencies are being boosted by 5 dB when EQ is engaged. Your hypothesis is that adding an MBM might allow the system to play cleaner, which we can only prove by temporarily replacing the third ULS-15 with the MBM, re-running the Audyssey calibration, and taking new measurements.

While this would be an interesting exercise, I must admit that I am quite pleased with the bass response in my current configuration. It is smooth, and integrates with the satellite speakers very well. However, if HSU Research is ever interested in having one of your good customers conduct tests to see how an MBM integrates into an environment with true subs and Audyssey calibration, I would be willing to volunteer. Just let me know when the unit ships! :)

Thank you, Dr Hsu, for your valued feedback.

Regards,
Jerry

It took me a little time to understand what you mean when you say that the low frequencies are being boosted by 5 dB when EQ is engaged. Your hypothesis is that adding an MBM might allow the system to play cleaner, which we can only prove by temporarily replacing the third ULS-15 with the MBM, re-running the Audyssey calibration, and taking new measurements.

While this would be an interesting exercise, I must admit that I am quite pleased with the bass response in my current configuration. It is smooth, and integrates with the satellite speakers very well. However, if HSU Research is ever interested in having one of your good customers conduct tests to see how an MBM integrates into an environment with true subs and Audyssey calibration, I would be willing to volunteer. Just let me know when the unit ships! :)

Thank you, Dr Hsu, for your valued feedback.

Regards,
Jerry

HaHa Jerry... bribes might work. ;) When you get done with it just ship it to me and I'll make sure the good Dr gets it back. :D

It took me a little time to understand what you mean when you say that the low frequencies are being boosted by 5 dB when EQ is engaged. Your hypothesis is that adding an MBM might allow the system to play cleaner, which we can only prove by temporarily replacing the third ULS-15 with the MBM, re-running the Audyssey calibration, and taking new measurements.

While this would be an interesting exercise, I must admit that I am quite pleased with the bass response in my current configuration. It is smooth, and integrates with the satellite speakers very well. However, if HSU Research is ever interested in having one of your good customers conduct tests to see how an MBM integrates into an environment with true subs and Audyssey calibration, I would be willing to volunteer. Just let me know when the unit ships! :)

Thank you, Dr Hsu, for your valued feedback.

Regards,
Jerry

If you are sane, just use your system as is. But I have yet to come across a sane audiophile! :D Ausiophiles always wants to tweak and improve. :)

The higher headroom comes from four factors - the MBM, especially in the nearfield position, has tremendous mid bass headroom. Second, the ULSs when relieved from having to handle mid bass, has all its amplifier power reserved just for deep bass. Thirdly, you can position the ULSs for highest efficiency in the low bass and not worry about it's mid bass efficiency. Last but not least, you are bi-amping the bass. Bi-amping has the advantage that even when one reaches the limit, if the other is still clean, the overall perceived distortion is lower.

Measuring the frequency responses does not tell you how much more headroom you can get from the ULS-MBM combo, but will let us determine the optimal location to place the ULSs to get the highest possible headroom.

The easiest way to find out which is the best spot for the low bass is to put one ULS at your listening position, at ear level. Put your mic at all the possible locations to put the ULSs. Get a response curve for each location. At each location, place the mic where the ULS dustcap would be if placed there. Make sure the tests are run for each location without any level changes. When you are done, super impose all the curves. Place the sub at the location where the low bass is the highest.

Is it possible to stack the ULSs? Once you find the best low bass location, you might want to stack all three ULS there.

I must admit, dr.HSU you have really given some unbelievably invaluable information for the past week you were here. I, for one, appreciate this greatly, and hope you continue to be active on the thread as I,myself, always seem to have an issue with my subs. Thank you greatly once again.

I must admit, dr.HSU you have really given some unbelievably invaluable information for the past week you were here. I, for one, appreciate this greatly, and hope you continue to be active on the thread as I,myself, always seem to have an issue with my subs. Thank you greatly once again.

Thank you for your kind words! Yes, I plan to be active from this point on.

Hi everyone just placed an order for a Rosenut ULS 15. I've been following the thread about a year waiting for this sub and was finally able to pull the trigger with my bonus. The support from Pete, Dr. Hsu and HTG were a big positive for me as was the concept and performance of the sub. Seemed to have everything I was looking for and I can already tell it's a wonderful company. The only thing I could have wanted is a cherry finish but looking at the pics this finish looks gorgeous and should look great with my existing speakers. Rosenut seems to be a very smart compromise between walnut and cherry type finishes.

I do have a large open style room so conventional wisdom is I should have gone ported but I plan on eventually getting a dual drive and am more concerned with sound quality and extension than output as I don't listen at reference. I'm also coming off of a little 8" sealed sub so I'm sure this will blow me away. I was planning on going for more of a far field corner placement with this one. I don't have too many placement options but there is also a near field placement basically in a open sided end table to the right of my couch I could try as well. This would be between the wall and couch. I would probably prefer the far placement so I can see the sub but if there is a significant SQ difference I'm game to try it. I haven't done much with measurements but would like to get more involved with it so I will likely pick up a radio shack meter and REW in the future but first I'm just going to enjoy this bad boy for a while first. So I'm glad to finally join the club and looking forward to learning as much as I can from you guys!

Hi everyone just placed an order for a Rosenut ULS 15. I've been following the thread about a year waiting for this sub and was finally able to pull the trigger with my bonus. The support from Pete, Dr. Hsu and HTG were a big positive for me as was the concept and performance of the sub. Seemed to have everything I was looking for and I can already tell it's a wonderful company. The only thing I could have wanted is a cherry finish but looking at the pics this finish looks gorgeous and should look great with my existing speakers. Rosenut seems to be a very smart compromise between walnut and cherry type finishes.

I do have a large open style room so conventional wisdom is I should have gone ported but I plan on eventually getting a dual drive and am more concerned with sound quality and extension than output as I don't listen at reference. I'm also coming off of a little 8" sealed sub so I'm sure this will blow me away. I was planning on going for more of a far field corner placement with this one. I don't have too many placement options but there is also a near field placement basically in a open sided end table to the right of my couch I could try as well. This would be between the wall and couch. I would probably prefer the far placement so I can see the sub but if there is a significant SQ difference I'm game to try it. I haven't done much with measurements but would like to get more involved with it so I will likely pick up a radio shack meter and REW in the future but first I'm just going to enjoy this bad boy for a while first. So I'm glad to finally join the club and looking forward to learning as much as I can from you guys!

Welcome to the Hsu 'family'! Please post your room layout so I can give suggestions for sub placement.

I was wondering about the suggestion from dr.HSU about the MBM, would the bass not be localised from the MBM? Since it's between 50-150 Hz and directly behind me, would it still seem like the bass is coming from the front stage?

Welcome to the Hsu 'family'! Please post your room layout so I can give suggestions for sub placement.

Thanks Dr. Hsu glad to joiin the family!

Here's a layout I was able to build. Some of these are off by 1" or so because I wasn't so precise with my mouse clicking but everything is farily close. I have 8 foot ceilings. The two boxes show the two placement options I was discussing earlier but I could also probably go along the far back wall as well as the other side of the TV. Just let me know if you needed other dimensions or info. Thanks for the help, I really appreciate it!

I was wondering about the suggestion from dr.HSU about the MBM, would the bass not be localized from the MBM? Since it's between 50-150 Hz and directly behind me, would it still seem like the bass is coming from the front stage?

What is amazing is if you do not set the MBM level too high, for me at least, you cannot tell the bass is coming from behind you! Of course, one usually do not crossover that high. 80 Hz is the norm, but I have tried as high as 150 Hz and it still is not localizable. When I give demos, people are always amazed - the bass is coming from THERE??? :D I find directly behind is much harder to localize than to my side.

Thanks Dr. Hsu glad to joiin the family!

Here's a layout I was able to build. Some of these are off by 1" or so because I wasn't so precise with my mouse clicking but everything is farily close. I have 8 foot ceilings. The two boxes show the two placement options I was discussing earlier but I could also probably go along the far back wall as well as the other side of the TV. Just let me know if you needed other dimensions or info. Thanks for the help, I really appreciate it!

Very nice sketch! I would place the sub either next to your sofa or directly behind the sofa if that is feasible (not the best position for WAF, but if you are single, that would work well!) I would set the ULF Trim to 50 Hz (the point where the response would start to roll off GENTLY - in your room, you should get strong bass down to 20 Hz even at this setting)

Very nice sketch! I would place the sub either next to your sofa or directly behind the sofa if that is feasible (not the best position for WAF, but if you are single, that would work well!) I would set the ULF Trim to 50 Hz (the point where the response would start to roll off GENTLY - in your room, you should get strong bass down to 20 Hz even at this setting)

Thanks, I just used sweet home 3D which was a free download. I was going to just try something in paint but did a search and found this software which worked great and was really easy to use. It had grid lines in feet and lots of pre loaded items so you could get the layout right without too much work.

I can put the sub inside my end table next to the couch so that placement should work fine. Behind the couch would be tough because that is a dining room but on the side of the couch would work well (thanks to that wireless capability!).

I was just curious what your thoughts were on receivers where you can set different crossovers for each speaker. I've heard that the reason some receivers only allow you to set one global crossover is because that is actually beneficial to just have one crossover but I've hear others suggest setting individual crossovers if you can. All of my speakers can go to 60-80 hz fairly easily so I'll probably set them to the same crossover until I can start measuring but I've always been curious about which approach is better. Thanks!

Thanks, I just used sweet home 3D which was a free download. I was going to just try something in paint but did a search and found this software which worked great and was really easy to use. It had grid lines in feet and lots of pre loaded items so you could get the layout right without too much work.

I can put the sub inside my end table next to the couch so that placement should work fine. Behind the couch would be tough because that is a dining room but on the side of the couch would work well (thanks to that wireless capability!).

I was just curious what your thoughts were on receivers where you can set different crossovers for each speaker. I've heard that the reason some receivers only allow you to set one global crossover is because that is actually beneficial to just have one crossover but I've hear others suggest setting individual crossovers if you can. All of my speakers can go to 60-80 hz fairly easily so I'll probably set them to the same crossover until I can start measuring but I've always been curious about which approach is better. Thanks!

In general, 80 Hz crossover works great for all speakers. It tend to give you the best dynamic range out of your receiver (crossing over lower means the receiver's amps have to use more of it's power for some bass, making it run out of steam earlier for the mids and highs). Off hand I am not sure which of the new receivers have separate crossover frequency setting for each channel. Perhaps other readers can chime in regarding what their receivers can do?

Go with the end table option. It should be great there.

BTW, I saw that there is a clearance of Sherwood R972s - normally $1800, now $599 plus shipping! It is the only receiver with Trinnov room EQ. Fox Studios use Trinnov for their studios, and costs them over $10,000 a pop, but you can get it in a $599 receiver...

BTW, I saw that there is a clearance of Sherwood R972s - normally $1800, now $599 plus shipping! It is the only receiver with Trinnov room EQ. Fox Studios use Trinnov for their studios, and costs them over $10,000 a pop, but you can get it in a $599 receiver...

There was a discussion on another AVS thread regarding the Sherwood fire sale. Seems as this particular model has been having some issues, so anyone considering it should do the homework.

If you are sane, just use your system as is. But I have yet to come across a sane audiophile! :D Ausiophiles always wants to tweak and improve. :)



Once again, you are correct, Dr Hsu. I am going to be conservative and enjoy my system as currently configured. Thank you for an interesting discussion, and your thoughtful feedback.

Regards,
Jerry

In general, 80 Hz crossover works great for all speakers. It tend to give you the best dynamic range out of your receiver (crossing over lower means the receiver's amps have to use more of it's power for some bass, making it run out of steam earlier for the mids and highs). Off hand I am not sure which of the new receivers have separate crossover frequency setting for each channel. Perhaps other readers can chime in regarding what their receivers can do?

Go with the end table option. It should be great there.

BTW, I saw that there is a clearance of Sherwood R972s - normally $1800, now $599 plus shipping! It is the only receiver with Trinnov room EQ. Fox Studios use Trinnov for their studios, and costs them over $10,000 a pop, but you can get it in a $599 receiver...

Thanks Dr. Hsu I'll just keep them at 80. I'm actually picking up a receiver that will do separate crossovers but just wasn't sure if there was a benefit to it unless you had small satelites that had to be crossed over higher. I'm trying out the Denon 4311 and hopefully going to the Audessey pro calibration eventually. I really like what the height channels add in PLIIz so I'm going to go with a 9.1 setup. It will also do separate EQ for 2 subs (level and distance for each) so I'd eventually like to get a second ULS to even out the response. I haven't heard much about Trinnov though so thanks for mentioning that, I'll take a look at that as it sounds interesting.

Thanks Dr. Hsu I'll just keep them at 80. I'm actually picking up a receiver that will do separate crossovers but just wasn't sure if there was a benefit to it unless you had small satelites that had to be crossed over higher. I'm trying out the Denon 4311 and hopefully going to the Audessey pro calibration eventually. I really like what the height channels add in PLIIz so I'm going to go with a 9.1 setup. It will also do separate EQ for 2 subs (level and distance for each) so I'd eventually like to get a second ULS to even out the response. I haven't heard much about Trinnov though so thanks for mentioning that, I'll take a look at that as it sounds interesting.

You are most welcome!

Once again, you are correct, Dr Hsu. I am going to be conservative and enjoy my system as currently configured. Thank you for an interesting discussion, and your thoughtful feedback.

Regards,
Jerry

But as a crazy audiophile, I would still like to see what the responses of the ULSs are like at each of the location without EQ and see what potential improvement add a MBM might do... :D

I've got a ULS-15 quad pack, so you'd think I could figure it out, but I'd like to know the input sensitivity for the unit. With the input gain at max, what is the signal level necessary to reach some known SPL, like 85 or 95 dB? Might best be measured outside, @ 1 m, or if in a room, using the typical THX woofer cal test signal so that the result isn't too warped by standing waves.

I've looked a bunch of subs and none state this. Is there a de facto standard across the industry?

I've got a ULS-15 quad pack, so you'd think I could figure it out, but I'd like to know the input sensitivity for the unit. With the input gain at max, what is the signal level necessary to reach some known SPL, like 85 or 95 dB? Might best be measured outside, @ 1 m, or if in a room, using the typical THX woofer cal test signal so that the result isn't too warped by standing waves.

I've looked a bunch of subs and none state this. Is there a de facto standard across the industry?

Wow, that is a nice subwoofer system! No, there are no standards. That number would not mean anything anyway. As long as the subs have enough gain to match your main speakers, the maximum gain has no relevance on how loudly the system can play, or how deep it can play, or how low the distortion you can get.

A single ULS will not have the output headroom of a PC/PB13 Ultra. I'd guess you would need at least two to match the output of a PB13, and even then you would need to co-locate them. Two ULS-15s would have a better room response, and perhaps better sound quality, if not output advantage. Two smaller and lighter subs are also a lot easier to deal with physically than one large sub, and easier to resell as well if you ever had to.

Jasmin....Need some questions answered first.
What size room and what do you plan to use it for....% of movies vs % of music? PB-13 is a ported sub vs the sealed ULS. Have you checked out the thread where ppl have offered to demo their subs? Even though you might not find the subs your are considering you could still take a listen to a ported sub vs a sealed sub to see which sound you prefer. Lastly the consensus is 2 subs work better in most rooms vs just one sub. With that in mind the PB-13 Ultra is $1999 delivered while the ULS-15 Dual drive is only slightly more at $2337.

But as a crazy audiophile, I would still like to see what the responses of the ULSs are like at each of the location without EQ and see what potential improvement add a MBM might do... :D

I would be glad to provide this information, but I am not sure I understand exactly what you want me to measure. Kindly suggest the measurement procedure you would like me to use, and I will do it. I have an REW kit with calibrated micrhone.

I would be glad to provide this information, but I am not sure I understand exactly what you want me to measure. Kindly suggest the measurement procedure you would like me to use, and I will do it. I have an REW kit with calibrated micrhone.

Put one ULS at your listening position, at ear level. Put your mic at all the possible locations to put the ULSs, and also where the MBM would go if you ever get one (directly behind your sweet spot. Put the mic on the floor since the MBM woofer would be close to the floor). Get a response curve for each location. At each location, place the mic where the ULS dustcap would be if placed there. Make sure the tests are run for each location without any level changes. When you are done, super impose all the curves. Disengage the equalizer for all these measurements.

Put one ULS at your listening position, at ear level. Put your mic at all the possible locations to put the ULSs, and also where the MBM would go if you ever get one (directly behind your sweet spot. Put the mic on the floor since the MBM woofer would be close to the floor). Get a response curve for each location. At each location, place the mic where the ULS dustcap would be if placed there. Make sure the tests are run for each location without any level changes. When you are done, super impose all the curves. Disengage the equalizer for all these measurements.

Ok, that is clear, Dr Hsu. Due to the level of effort, it may take several days before I complete the measurements. I'll post the results.

Jerry

Ok, that is clear, Dr Hsu. Due to the level of effort, it may take several days before I complete the measurements. I'll post the results.

Jerry

Thank you kindly! No hurry.

Thank you kindly! No hurry.

Sub measurements, part 1.

Two pics of my room. Pic of the ULS-15 sitting at ear height at the MLP. Pic of the EMM-6 mic at the same height as the ULS-15 dustcap.

Sub measurements, part 2

It's difficult to show nine measurement overlayed on the same graph. Hopefully the way I presented the measurements is useful. The existing sub location measurements don't look too bad, in my opinion. The MBM would go where sub 3 currently sits.

Sub measurements, part 1.

Two pics of my room. Pic of the ULS-15 sitting at ear height at the MLP. Pic of the EMM-6 mic at the same height as the ULS-15 dustcap.

I do not think I have seen your place before Jerry. It's looks nice and cosy. And I did not believe you would get those measurements that fast. :eek: Slow day today? :p

I do not think I have seen your place before Jerry. It's looks nice and cosy. And I did not believe you would get those measurements that fast. :eek: Slow day today? :p

Thanks! I am retired, so I have a lot of freedom. :)

Sub measurements, part 2

It's difficult to show nine measurement overlayed on the same graph. Hopefully the way I presented the measurements is useful. The existing sub location measurements don't look too bad, in my opinion. The MBM would go where sub 3 currently sits.

Wow, that was fast work! :eek: Great job! I like Alternate position 1 best. Below 20 Hz, and from 35 - 40 Hz, you get 3 - 4 dB more output than current front locations. Where is this location? For now, I would stack the two front ULSs there. If you ever itch to try out the MBM, I would put all three ULSs in that Alternate Position 1 location. :D

No, there are no standards. That number would not mean anything anyway. As long as the subs have enough gain to match your main speakers, the maximum gain has no relevance on how loudly the system can play, or how deep it can play, or how low the distortion you can get.Thanks much for the reply. I realize all that. However, it would still do me a lot of good to know that answer for Hsu subs in general, or the ULS-15 in particular.

I sometimes design bass processing circuits, as illustrated here (http://www.avsforum.com/avs-vb/showpost.php?p=19700913&postcount=49), using passive summing, which is a lossy process. So it would help to know how much signal I'll need to have at the end to reach a known SPL from the sub.

Pretty please? :o

I do not think I have seen your place before Jerry. It's looks nice and cosy. And I did not believe you would get those measurements that fast. :eek: Slow day today? :p

That is the advantage of what we call 'subwoofer crawling' method. Placing the sub in ONE location (where the listener would normally sit) and move the mic around! That is a heck of a lot easier and faster than moving the sub around. Switching the mic and source locations gives exactly the same results, so why not move the lighter object? Once you found the best location, then move the heavy object there!

Thanks much for the reply. I realize all that. However, it would still do me a lot of good to know that answer for Hsu subs in general, or the ULS-15 in particular.

I sometimes design bass processing circuits, as illustrated here (http://www.avsforum.com/avs-vb/showpost.php?p=19700913&postcount=49), using passive summing, which is a lossy process. So it would help to know how much signal I'll need to have at the end to reach a known SPL from the sub.

Pretty please? :o

Unless I am missing something about your passive summing (I don't quite understand why you had 4 arrows going from the 'Bass EQ' to the passive summing box, for example), you can just feed the output of the Marchand crossover to the left inputs of the ULSs and the sub out through the EQ into the right channel inputs of the ULSs? You don't need any passive summing.

How high do you have to set the volume on the subs right now? Note that since the subs are not all co-located in one spot, the SPL at your listening chair is not easily determined without any actual measurements. Best to just perform a measurement yourself. Put the SPL meter at ear level on your sweet spot (meter set to 'flat' position or if not to 'C'). Set the volume on all the subs to max. Play a 40 Hz tone and turn up the master volume on your processor till you get 90 dB. Then measure how many mV the summing box is putting out to the subs. This measurement will take into account all the acoustic interactions of your actual room (at some frequencies the output of one sub can be cancelling the output of another sub while summing at other frequencies).

Unless I am missing something about your passive summing (I don't quite understand why you had 4 arrows going from the 'Bass EQ' to the passive summing box, for example), you can just feed the output of the Marchand crossover to the left inputs of the ULSs and the sub out through the EQ into the right channel inputs of the ULSs? You don't need any passive summing.That would require running two audio cables to each sub instead of one. Everything was already wired and running by the time I discovered the rolloff in the BassQ.

There are 4 arrows because the BassQ has 4 separately tuned outputs, one for each subwoofer. It's a simplified form of Harman's SFM process.

The Marchand is ambiguously labeled as a crossover (that's what the unit does) but in my system it is only a 20 Hz low-pass filter. This is all in order to compensate for inherent rolloff in the BassQ unit. I didn't buy 4 ULS-15s to have the bottom end limited to 20 Hz!

The two outputs of the SSP carry the same signal, but the Aux out is time delayed 22 ms to compensate for the latency of the BassQ, so the <20Hz part of the spectrum splices perfectly back together with the EQ'd part >20Hz. And therein is another advantage of the passive summing: I can see the splice on a scope and with REW before the signal enters the sub. I guess I could have simulated it to prove out using the sub as the summing.

How high do you have to set the volume on the subs right now? Note that since the subs are not all co-located in one spot, the SPL at your listening chair is not easily determined without any actual measurements.They are not co-located because that would not have helped my room's modal cancellation problems.

Best to just perform a measurement yourself. Put the SPL meter at ear level on your sweet spot (meter set to 'flat' position or if not to 'C'). Set the volume on all the subs to max. Play a 40 Hz tone and turn up the master volume on your processor till you get 90 dB. Then measure how many mV the summing box is putting out to the subs. This measurement will take into account all the acoustic interactions of your actual room (at some frequencies the output of one sub can be cancelling the output of another sub while summing at other frequencies).I know how to measure it, being an EE and all. I just don't want to mess with the settings on the sub (set it to max, then try to return it to the original position) as they are calibrated by the BassQ so they interact a certain way to cancel room modes, and I don't want to haul out the mics to run it again. The system works and sounds great as it stands.

I just figured as the designer of the sub you might have the sensitivity information readily at hand. If not, or you prefer not to share it, that's perfectly OK. I was just asking.

Best regards,

That would require running two audio cables to each sub instead of one. Everything was already wired and running by the time I discovered the rolloff in the BassQ.

There are 4 arrows because the BassQ has 4 separately tuned outputs, one for each subwoofer. It's a simplified form of Harman's SFM process.

The Marchand is ambiguously labeled as a crossover (that's what the unit does) but in my system it is only a 20 Hz low-pass filter. This is all in order to compensate for inherent rolloff in the BassQ unit. I didn't buy 4 ULS-15s to have the bottom end limited to 20 Hz!

The two outputs of the SSP carry the same signal, but the Aux out is time delayed 22 ms to compensate for the latency of the BassQ, so the <20Hz part of the spectrum splices perfectly back together with the EQ'd part >20Hz. And therein is another advantage of the passive summing: I can see the splice on a scope and with REW before the signal enters the sub. I guess I could have simulated it to prove out using the sub as the summing.

They are not co-located because that would not have helped my room's modal cancellation problems.

I know how to measure it, being an EE and all. I just don't want to mess with the settings on the sub (set it to max, then try to return it to the original position) as they are calibrated by the BassQ so they interact a certain way to cancel room modes, and I don't want to haul out the mics to run it again. The system works and sounds great as it stands.

I just figured as the designer of the sub you might have the sensitivity information readily at hand. If not, or you prefer not to share it, that's perfectly OK. I was just asking.

Best regards,

If I have that info handy, I would have given it to you right away. That is just not something anyone has ever asked for, and I don't foresee anyone else asking for.. :D Apparently that holds true for other manufacturers you have contacted. No one has that data for you. If I ever pull out a ULS to measure outdoors in the near future, I will perform that test and let you know the results.

If I have that info handy, I would have given it to you right away. That is just not something anyone has ever asked for, and I don't foresee anyone else asking for.. :D Apparently that holds true for other manufacturers you have contacted. No one has that data for you.I have not contacted other manufacturers.

If I ever pull out a ULS to measure outdoors in the near future, I will perform that test and let you know the results.Thanks. That would be great. :)

Does not have to be the ULS, could be any of your subs. Might be interesting to check a few models over time to see how they range.

I have not contacted other manufacturers.

Thanks. That would be great. :)

Does not have to be the ULS, could be any of your subs. Might be interesting to check a few models over time to see how they range.

Will do. :)

May be potentially in the market for a dual drive. Looks like an awesome sub system!

Have a few questions...

After you set the ulf trim, what does the slope look like? Is it a natural sealed 12db second order rolloff?

Also, what kind of max output are you owners getting in room?

Can a single uls hit reference level in a medium sized room?

How about max output at 10hz or so? Again, a medium sized room.

My room is sealed, in a basement, and 2100 cubic feet.

Thanks for the help!

Are you getting a dual drive in addition to your current subs???? or will you be replacing the subs you have now with the DD?

They would be replacing my eDs. Outlaws would stay.

Just looking to try something different potentially.

May be potentially in the market for a dual drive. Looks like an awesome sub system!

Have a few questions...

After you set the ulf trim, what does the slope look like? Is it a natural sealed 12db second order rolloff?

Also, what kind of max output are you owners getting in room?

Can a single uls hit reference level in a medium sized room?

How about max output at 10hz or so? Again, a medium sized room.

My room is sealed, in a basement, and 2100 cubic feet.

Thanks for the help!

Can you post your room layout, or direct me to a post of your room layout?

The effect of the ULF trim is very gentle. The noted frequency on the ULF trim is the frequency at which the gentle slope starts. The slope is on the order of 2 dB/Oct. Only below 15 Hz that the sub rolls off steeply.

If you are after high SPL in the low bass, the 15H is a much better choice. It also has a sealed mode if you wish to explore the sealed mode. Do note that sealed mode will not provide high SPL in the low bass compared to the ported mode.

No commercial subs will put out high SPL at 10 Hz (other than the Eminent Technology's rotary woofer.) You do not want too SPL in the sub 10 Hz range as it can cause brain damage. :D

I would suggest a pair of 15Hs if it's mainly for HT.

Can you post your room layout, or direct me to a post of your room layout?

The effect of the ULF trim is very gentle. The noted frequency on the ULF trim is the frequency at which the gentle slope starts. The slope is on the order of 2 dB/Oct. Only below 15 Hz that the sub rolls off steeply.

If you are after high SPL in the low bass, the 15H is a much better choice. It also has a sealed mode if you wish to explore the sealed mode. Do note that sealed mode will not provide high SPL in the low bass compared to the ported mode.

No commercial subs will put out high SPL at 10 Hz (other than the Eminent Technology's rotary woofer.) You do not want too SPL in the sub 10 Hz range as it can cause brain damage. :D

I would suggest a pair of 15Hs if it's mainly for HT.

Hi Dr. Thanks for responding.

Picture of my room and current equipment are in my signature. Basically, it's an 18x14x8 ft sealed room. The ULS's would replace my 2 eD's in the front of my stage. I also have 2 Outlaw LFM1-EXs behind my HT seating. I'd likely corner load the ULSs behind the speakers to get the most boundry gain. With my eD's I was flat to 10hz. I was hoping that the ULS's would have more output from 10-20hz than my eDs. Just looking for more headroom. My room is such that I get a lot of gain.

I do play at reference level at times, and my current system has produced around 118db. With the ULSs, I'd like the to play to 115 or 116.

It is 100% HT.

I'm concerned somewhat with ported designs, because I like the extension down low.

Thanks for your input!

i dont know if this question has been asked before but to Dr.Hsu, what does "your" (personal) sub system consist of?

Hi Dr. Thanks for responding.

Picture of my room and current equipment are in my signature. Basically, it's an 18x14x8 ft sealed room. The ULS's would replace my 2 eD's in the front of my stage. I also have 2 Outlaw LFM1-EXs behind my HT seating. I'd likely corner load the ULSs behind the speakers to get the most boundry gain. With my eD's I was flat to 10hz. I was hoping that the ULS's would have more output from 10-20hz than my eDs. Just looking for more headroom. My room is such that I get a lot of gain.

I do play at reference level at times, and my current system has produced around 118db. With the ULSs, I'd like the to play to 115 or 116.

It is 100% HT.

I'm concerned somewhat with ported designs, because I like the extension down low.

Thanks for your input!

18 ft front to back and 14 ft left to right, correct? Placing subs behind you (where the EXs are) will have a null centered around 16 Hz. It would be better to put like a pair of MBMs back there for the great mid bass punch, and have the true subs up front.

I doubt much of the 118 dB is due to any 10 Hz content. No sealed subs will give high SPL in that range even with some help from room gain. If you can achieve strong output down to 16 Hz, that would be plenty, and quite an experience. I would go for two 15Hs up front from 50 Hz down, and two MBMs at the back from 50 Hz up. You can also stick to the EXs back there but add our HPF to filter out bass below 50 Hz. By keeping the lower bass out of the EXs, they have more power reserved to give you the punch in the mid bass.

Order the HPF with 15 Hz and 50 Hz filters. Try the 15 Hz filter on the EDs. See if you get any lower output (from your 118 dB) with the 15 Hz filter engaged. I think you will see little difference. :D

i dont know if this question has been asked before but to Dr.Hsu, what does "your" (personal) sub system consist of?

Due to WAF factor, I only have a VTF-2 MK2 in my house. When I want great bass, all I have to do is go into work... :D Our demo room has two 15Hs, and two ULSs. Strange as it may sound, I don't listen very loudly. I feel sick if I sit in front of one of the 15Hs when playing the haunting. :D

do you have the 15Hs mixed with the ULS, or are they separate rooms for each set?

18 ft front to back and 14 ft left to right, correct? Placing subs behind you (where the EXs are) will have a null centered around 16 Hz. It would be better to put like a pair of MBMs back there for the great mid bass punch, and have the true subs up front.

I doubt much of the 118 dB is due to any 10 Hz content. No sealed subs will give high SPL in that range even with some help from room gain. If you can achieve strong output down to 16 Hz, that would be plenty, and quite an experience. I would go for two 15Hs up front from 50 Hz down, and two MBMs at the back from 50 Hz up. You can also stick to the EXs back there but add our HPF to filter out bass below 50 Hz. By keeping the lower bass out of the EXs, they have more power reserved to give you the punch in the mid bass.

Order the HPF with 15 Hz and 50 Hz filters. Try the 15 Hz filter on the EDs. See if you get any lower output (from your 118 dB) with the 15 Hz filter engaged. I think you will see little difference. :D

It's funny that you should say such since i have heard members state how "everything" needs to be replicated on the disc to have a "full" movie experience.

I will ask a direct question, are you saying, even if a sub system is capable of reference levels at 10Hz or below, a system capable of 16Hz should provide just as good an experience as a system capable of 10Hz?

do you have the 15Hs mixed with the ULS, or are they separate rooms for each set?

They are all set up in the same room, with a switcher to switch between the different subs (VTF-1, VTF-2 MK4, VTF-3 MK4, MBM, etc.)

It's funny that you should say such since i have heard members state how "everything" needs to be replicated on the disc to have a "full" movie experience.

I will ask a direct question, are you saying, even if a sub system is capable of reference levels at 10Hz or below, a system capable of 16Hz should provide just as good an experience as a system capable of 10Hz?

No. what I am saying is there are nothing I know out there (other than the rotary woofer) that will be able to give reference level at 10 Hz. If the subwoofer is not capable of reference level at 10 Hz, with or without the 10 Hz, it will not make any difference. This is especially true regarding measurable output differences - even with the reference level capable 10 Hz sub, with most program material, most of the energy is at other frequencies. So, with or without the 10 Hz, the measurable dB you get will not be measurably different. :D

Ok, so let me see if i have this understood:

If i have a sub system capable of reference level 10Hz output, then it DOES make a difference with 10Hz material in a source.

If the system is not 10Hz capable then it DOES NOT make a difference if the 10Hz info is in or not?

My understanding then is, only if a sub system can hit reference does it affect 10Hz material???

If it can produce 10Hz but NOT at reference then it makes no difference?

Ok, so let me see if i have this understood:

If i have a sub system capable of reference level 10Hz output, then it DOES make a difference with 10Hz material in a source.

If the system is not 10Hz capable then it DOES NOT make a difference if the 10Hz info is in or not?

My understanding then is, only if a sub system can hit reference does it affect 10Hz material???

If it can produce 10Hz but NOT at reference then it makes no difference?

First, few material have 10 Hz in the program. Second, even when present, the 10 Hz level relative to the sum of the energy at all the other bass frequencies is probably miniscule. Hence, even if the sub can reproduce the 10 Hz faithfully and thus maintain the same output relative to the other bass frequencies, the dB reading that you get on the SPL meter will not change significantly whether the 10 Hz is there or not. To further compound the situation, even at the same dB output, 10 Hz would be much harder to detect than the higher bass. The presence of the higher bass tend to have a great masking effect. That said, if the 10 Hz does cause your floor to heave so you can feel your sofa move, then it will make a difference. If you are on a concrete floor, probably not much difference. When I was demonstrating the ULS, the walls of the demo room seem to be quite sensitive to very low frequencies. Leaning against the wall, one can feel it moving to the very low frequency. Sitting in the listening chair on a concrete floor, I was not aware of any 10 Hz. Of course, if you can find a source that has a pretty pure 10 Hz energy at high levels without any masking from higher bass, the 10 Hz reference level capable system will make a huge difference. Just like in the movie Pulse where they have a strong quite pure 19 Hz heart beat, it made a big difference whether your sub can generate reference level 19 Hz. In movies that have some 20 Hz, but only together with a lot of higher bass that are much louder than the 20 Hz content, the presence or absence of 20 Hz would be subtle. But that is what audiophiles are - they want to make sure all signal are present in the right proportions irrespective of how subtle the effect may be. :D

Ok, I think I understand. So my next question is can a quad drive produce reference level SPLs at 10Hz in a typical listening room?

What do you consider a typical listening room? Also, what is meant by reference? 105 db? THX peak reference levels? That would be 115 db for bass.

What do you consider a typical listening room? Also, what is meant by reference? 105 db? THX peak reference levels? That would be 115 db for bass.

Yes,115dB for bass. Also, typical is very general, I know but that is what is used regularly by manufacturers. So let's just say, for argument's sake, a normal living room, 3000^3 ft.

Yes,115dB for bass. Also, typical is very general, I know but that is what is used regularly by manufacturers. So let's just say, for argument's sake, a normal living room, 3000^3 ft.

I don't think any subwoofer out there can put out 115 dB at 10 Hz, other than the rotary woofer.

I too don't think there is any SINGLE sub that can do that but there has to be a subwoofer SYSTEM that can. There are many members who claim they get that output from their system, so that is why I mentioned the quad drive, because I know how well regarded the quad drive is.

I don't think any subwoofer out there can put out 115 dB at 10 Hz, other than the rotary woofer.

How about multiple subwoofers in a room? Can the combined response equal 115db at 10hz. I think that's what kimwyn is asking, specifically for the quad drive.

Edit: he beat me too it!

I too don't think there is any SINGLE sub that can do that but there has to be a subwoofer SYSTEM that can. There are many members who claim they get that output from their system, so that is why I mentioned the quad drive, because I know how well regarded the quad drive is.

They claim they get 115 dB at 10 Hz from their system?? What system do they have? If you have 8 LMS5400, then maybe (18" woofers with like 3 - 4" peak to peak linear excursion).

How about multiple subwoofers in a room? Can the combined response equal 115db at 10hz. I think that's what kimwyn is asking, specifically for the quad drive.

Edit: he beat me too it!

Even a quad drive will not do 115 dB at 10 Hz. As I said, maybe 8 LMS5400 can do it.

When is the best time to come in for a demo? Are you ever open on the weekends?

When is the best time to come in for a demo? Are you ever open on the weekends?

Tuesdays through Fridays are best. Mondays are bad (orders and phone calls accumulated over the weekend). If you cannot make it during regular office hours, arrangements can be made for after hours during weekdays.

Hi Dr. Hsu,

Heard back from an old friend in the sub business, Ken Kreisel, who started M&K. He confirmed their THX subs had 89 dB sensitivity (1m, 100 mV), in the Cal position, and 12-15 extra gain beyond that, so as to be in the same ballpark as most other subs. (Some have even more than that.)

Since Hsu has no distribution in Norway, I'll mention Kreisel has just launched his new products (http://www.lsound.no/Info/nyheter/article_609847.art.aspx) there.

Hi Dr. Hsu,

Heard back from an old friend in the sub business, Ken Kreisel, who started M&K. He confirmed their THX subs had 89 dB sensitivity (1m, 100 mV), in the Cal position, and 12-15 extra gain beyond that, so as to be in the same ballpark as most other subs. (Some have even more than that.)

Since Hsu has no distribution in Norway, I'll mention Kreisel has just launched his new products (http://www.lsound.no/Info/nyheter/article_609847.art.aspx) there.

Thanks for the info. Is that measured in half space outdoors?

Thanks for the info. Is that measured in half space outdoors?He did not say, but I'd guess so, being the measurement fanatic that he is.

Mr. Mansfield (ex-THX) mentioned that THX subs usually came in a couple dB hotter than the specified 89 dB in their 3000 cu' IEC testing room @ 12'. But he did not say where it was placed in the room.

I have just received my ULS-15 and am going through the procedure of setting it up. I have a few questions...

How do I set the ULF trim? I don't understand what it actually does.

I have set the ULS volume to about 10 o'clock and manually set the sub-output level from my receiver (Pioneer VSX-1120K) to +4dB. Still I need to have the receiver's master volume quite loud for the sub to come on from standby mode. Am I doing something wrong?

I am using a Galaxy Audio CM-140 Check Mate SPL Meter (http://www.galaxyaudio.com/CM140.php) and it has a 'C' mode for low frequencies. Should I use 'C' mode for measuring the sub-woofer? Or just stick to 'A' mode?

I have just received my ULS-15 and am going through the procedure of setting it up. I have a few questions...

How do I set the ULF trim? I don't understand what it actually does.

I have set the ULS volume to about 10 o'clock and manually set the sub-output level from my receiver (Pioneer VSX-1120K) to +4dB. Still I need to have the receiver's master volume quite loud for the sub to come on from standby mode. Am I doing something wrong?

I am using a Galaxy Audio CM-140 Check Mate SPL Meter (http://www.galaxyaudio.com/CM140.php) and it has a 'C' mode for low frequencies. Should I use 'C' mode for measuring the sub-woofer? Or just stick to 'A' mode?

Congrats for getting a ULS!

Did you set all the main speakers to small, 80 Hz crossover? Large speaker settings, or low crossover points reduces the amount of bass going to the sub. Also, feel free to leave the sub in the 'on' position instead of 'auto' position. The sub will draw the same power in either mode.

You definitely have to use the 'C' mode. A mode will not measure any bass frequencies.

Do post your room layout. Include all dimensions, distance of your ears from nearest walls when seated in your best LP, which spots in the room you can put the sub, and details of adjoining rooms that you can acoustically couple your main room to by keeping doors open, etc. Best deep bass performance may be when you leave those doors open! :D

Since you have a means of measuring, place the sub in your best LP, woofer at ear level. Play the test tones and put your SPL meter at the different locations where you can place the subwoofer. With the same test tone level, plot out the absolute SPL reading at all the possible locations for the subwoofer. Do a set of curves for doors closed, and doors open. If there are more than one door, you should do it for door 1 open + door 2 closed, door 1 closed + door 2 open, etc. Post all the graphs and I will help you pick the 'best' location for the sub, and which door(s) to keep open when listening.

Congrats for getting a ULS!Thanks! Even without any fine tuning it already sounds fantastic!

Did you set all the main speakers to small, 80 Hz crossover?Yup.

Do post your room layout. Include all dimensions, distance of your ears from nearest walls when seated in your best LP, which spots in the room you can put the sub, and details of adjoining rooms that you can acoustically couple your main room to by keeping doors open, etc. Best deep bass performance may be when you leave those doors open! :DI have attached a sketch done in Google Sketchup, which I am terrible at using. Hopefully it gives you enough info. The best LP is on the couch, centered between the two main speakers. (I don't know what the dark patch on the couch is, I am bad at Sketchup). The opening in the top left has no door, so it is always open. It leads to an entrance hall, which has two small rooms off it. At the far end of the hall, a door-less doorway leads to a large open plan floor area.

place the sub in your best LP, woofer at ear levelYou say this so nonchalantly and I don't know whether to laugh or cry. :eek: It was hard enough for me just to get the ULS into the corner. ;) But all joking aside, the corner is vastly preferable due the WAF and I would really like to just tweak it to the optimum settings for that position.

Thanks! Even without any fine tuning it already sounds fantastic!

Yup.

I have attached a sketch done in Google Sketchup, which I am terrible at using. Hopefully it gives you enough info. The best LP is on the couch, centered between the two main speakers. (I don't know what the dark patch on the couch is, I am bad at Sketchup). The opening in the top left has no door, so it is always open. It leads to an entrance hall, which has two small rooms off it. At the far end of the hall, a door-less doorway leads to a large open plan floor area.

You say this so nonchalantly and I don't know whether to laugh or cry. :eek: It was hard enough for me just to get the ULS into the corner. ;) But all joking aside, the corner is vastly preferable due the WAF and I would really like to just tweak it to the optimum settings for that position.

Isn't your real name Schwarzenegger?? :confused: Lifting the ULS should be a piece of cake! :eek: :D OK. We will stick to that location. Given that there are no other options regarding keeping doors open or closed, and the sub location is fixed, there is not much more I can help with :D. Just play around with the ULF Trim. Setting that to 50 Hz should give you a bit tighter bass. The ULF Trim frequency is where the bass starts to roll off GENTLY. The roll off rate is about 2 dB/Oct. So, even when set to 50 Hz, it's down only 4 dB at 15 Hz. The higher setting also gives you more headroom.

hey Dr.Hsu, take a look at this. (http://www.avsforum.com/avs-vb/showpost.php?p=21799980&postcount=1225)

I assume this is what you meant but 130dB at 10Hz :eek::eek::eek::eek::eek::eek::eek::eek: thats a bit on the ridiculous side. Is all that even needed? Any of the trip or quad drive owners in here ever measured their systems SPL capabilities at different frequencies? What did you guys come up with?

Hi folks! I've been reading this thread as I'm trying to chose between ULS-15 Dual Drive and 2 Rythmik F15hp. I've noticed that's there hasn't been a lot of talk about the wireless feature. Are any of you using it? Any sonic(signal strength,s/n) differences between wireless and cable? I'm trying to decide if this is something I would use with sound quality being my top priority. My subs would be about 10 ft. from my pre/pro,but 30 ft. of cable away. Any thoughts? Thanks in advance!

I use the wireless on the ULS. I believe the signal strength is about the same and so is the sound quality. Some people, like me, have had success with it, others have had other wireless stuff interfere with the signal. There are things that you can do if you run into interference that have helped out some guys, but there are those who had no luck and ended up using the wired connection.

I am one who has never been able to get the wireless connection to work static-free. I have a lot of wireless signals in my home. My recommendation would be that if a wireless connection is a "must have", make sure you can return the sub if you can't get it to work to your satisfaction. If wireless is just a "nice to have", and you can fall back to a wired connection, then you won't be disappointed with the ULS-15.

hey Dr.Hsu, take a look at this. (http://www.avsforum.com/avs-vb/showpost.php?p=21799980&postcount=1225)

I assume this is what you meant but 130dB at 10Hz :eek::eek::eek::eek::eek::eek::eek::eek: thats a bit on the ridiculous side. Is all that even needed? Any of the trip or quad drive owners in here ever measured their systems SPL capabilities at different frequencies? What did you guys come up with?

I doubt it can hit 130 dB at 10 Hz, but 115 dB, doable.

Dr Hsu,

I need your advice, please. I am considering purchasing a 4th ULS-15, and would like your opinion regarding where you would place the sub. A picture of my listening room was posted previously here (http://www.avsforum.com/avs-vb/showthread.php?p=21768487#post21768487), as well as response measurements.

Of course, I will experiment with placement options and take measurements, but I am looking for a starting point. Several options are:

1. Placing the 4th sub next to, or on top of, the 3rd sub in the rear of the room, which is very close to my MLP.

2. Placing all 4 subs in the front of the room, two on either side of the display, stacked on top of eachother.

I have no experience with stacking subs. It would seem to me that the response of the sub on top would differ from the sub on the bottom, is that correct? Is stacking a option that you recommend?

Your guidance would be greatly appreciated.

Dr Hsu,

I need your advice, please. I am considering purchasing a 4th ULS-15, and would like your opinion regarding where you would place the sub. A picture of my listening room was posted previously here (http://www.avsforum.com/avs-vb/showthread.php?p=21768487#post21768487), as well as response measurements.

Of course, I will experiment with placement options and take measurements, but I am looking for a starting point. Several options are:

1. Placing the 4th sub next to, or on top of, the 3rd sub in the rear of the room, which is very close to my MLP.

2. Placing all 4 subs in the front of the room, two on either side of the display, stacked on top of eachother.

I have no experience with stacking subs. It would seem to me that the response of the sub on top would differ from the sub on the bottom, is that correct? Is stacking a option that you recommend?

Your guidance would be greatly appreciated.

If possible put all four in alternate position 1, the red curve on the second graph. That seems to give the highest low bass and still pretty good mid and upper bass.

Yes, the subs that are further off the ground will have a dip in the upper bass, but if each sub has a dip at a different frequency, the end result would be a smoother overall curve than any one position. They are close enough to each other so there is no cancellation between the subs. All in all a big plus to stack all in one corner. Just make sure no earthquake! :D

If possible put all four in alternate position 1, the red curve on the second graph. That seems to give the highest low bass and still pretty good mid and upper bass.

Yes, the subs that are further off the ground will have a dip in the upper bass, but if each sub has a dip at a different frequency, the end result would be a smoother overall curve than any one position. They are close enough to each other so there is no cancellation between the subs. All in all a big plus to stack all in one corner. Just make sure no earthquake! :D

Hey Doc....IIRC Pete always advocated not to stack the subs cause of what I think he said floor bounce and always recommended placing the subs next to each other in order to co-locate the subs. Could you clarify that thinking?

@ Jerry. Slow down dude I just bought the third one. :p

@ Jerry. Slow down dude I just bought the third one. :p

What can I say, the market has been good lately.... :)

See, I told you AL, it's a must to have 4 of these subs. I think I'll go that route also before year end. So let me know how you fear with the 4th Jerry.

Hey Doc....IIRC Pete always advocated not to stack the subs cause of what I think he said floor bounce and always recommended placing the subs next to each other in order to co-locate the subs. Could you clarify that thinking?

@ Jerry. Slow down dude I just bought the third one. :p

It can go either way. Try placing the mic at the alternate side-by-side locations and see what the differences in response is like. If not much difference, AND you have the space available, great! However, few people have the floor space to accommodate multiple subs, especially a Quad Drive!

Locating one sub some distance off the floor will not be ideal a dip at one frequency. A stack of multiple subs is more akin to a line source sub which should have a pretty good response. A stack of 4 ULSs would almost reach the ceiling, making it a true 'line source'!

If possible put all four in alternate position 1, the red curve on the second graph. That seems to give the highest low bass and still pretty good mid and upper bass.

Dr Hsu, please refer to the attached measurement graph (attachment 1). The blue line represents an averaged response for the two existing subs in the front of the room. The red line represents "Alternate Position 1". I am programed to select the sub positions that yield the smoothest response in the 10-100Hz range. From my perspective, this would be the blue line.

True, the red line shows a 2-3 dB higher output below 30 Hz. But is this higher output worth compromising the overall smoother response represented by the blue line?

My listening tastes are more towards music. I am not inclined to sit around all day listening to action movies with earth-shaking explosions. Might this suggest that the blue-line response is a better match for my tastes?

And the EQ'ed bass response (3 subs + LR mains) (attachment 2) looks pretty smooth to me. Why is this not the best placement for my subs?

Sorry for all the questions--I'm just trying to become better educated.

A stack of four ULS subs.. I would love to have a couple of those flanking my screen, an octo-drive... *off to the gas station to buy a roll of lotto tickets*

Hey Dr, just for the sake of argument, do you think the bottom ULS could support the weight of the top three in such an arrangement?

A stack of four ULS subs.. I would love to have a couple of those flanking my screen, an octo-drive... *off to the gas station to buy a roll of lotto tickets*

Hey Dr, just for the sake of argument, do you think the bottom ULS could support the weight of the top three in such an arrangement?

Not a problem. However, I would remove the feet (the feet cannot take that weight), and put a cloth or something between the subs.

Locating one sub some distance off the floor will not be ideal a dip at one frequency.
I asked Pete about stacking ULS-15s when I bought my Quad a couple of years back and he also stated this - probably somewhere up in 80Hz or so range I suppose and likely audible.

What are your thoughts about how far subs can be apart before co-location benefits diminsh? I have read anything from 1/4 to 1/2 wavelength. Right now my Quad has each on the floor spaced about equally across a 12 foot wall. If my thinking is correct, each should be within the co-location distance with the next one over. Is that correct? Regardless, performance is spectacular:D

Dr Hsu, please refer to the attached measurement graph (attachment 1). The blue line represents an averaged response for the two existing subs in the front of the room. The red line represents "Alternate Position 1". I am programed to select the sub positions that yield the smoothest response in the 10-100Hz range. From my perspective, this would be the blue line.

True, the red line shows a 2-3 dB higher output below 30 Hz. But is this higher output worth compromising the overall smoother response represented by the blue line?

My listening tastes are more towards music. I am not inclined to sit around all day listening to action movies with earth-shaking explosions. Might this suggest that the blue-line response is a better match for my tastes?

And the EQ'ed bass response (3 subs + LR mains) (attachment 2) looks pretty smooth to me. Why is this not the best placement for my subs?

Sorry for all the questions--I'm just trying to become better educated.

Are those responses of the subs only, or sub + main speakers? Curious why you have a sharp dip at 60 Hz with the Alternate 1 position. If it is sub + mains, and you are crossing over at 60 Hz to the mains, try measuring with the phase inverted, in that position.

Are those responses of the subs only, or sub + main speakers? Curious why you have a sharp dip at 60 Hz with the Alternate 1 position. If it is sub + mains, and you are crossing over at 60 Hz to the mains, try measuring with the phase inverted, in that position.

This response was for the sub only. I suspect the dip is the room response at that location. The initial measurement graphs I posted had 1/6 octave smoothing, which masked the narrow dip at 60 Hz. This graph has no smoothing. Setting on sub: crossover out, phase 0, ULF trim 16 Hz.

I still think my current position is better than Alternate 1. Would you agree?

I asked Pete about stacking ULS-15s when I bought my Quad a couple of years back and he also stated this - probably somewhere up in 80Hz or so range I suppose and likely audible.

What are your thoughts about how far subs can be apart before co-location benefits diminsh? I have read anything from 1/4 to 1/2 wavelength. Right now my Quad has each on the floor spaced about equally across a 12 foot wall. If my thinking is correct, each should be within the co-location distance with the next one over. Is that correct? Regardless, performance is spectacular:D

One sub up high would have a dip, but a whole stack that goes essentially from floor to ceiling becomes a line source, and should not exhibit any significant dip from floor bounce/ceiling bounce. This is particularly true for the ULSs since the woofers stretch pretty close to the ends of the cabinets so it's very close to a line source. Stacking 15Hs is less like a line source because the height of the cabinet is much more than the woofer diameter. If you want to create a line source with the 15H, you need to put them sideways. That way the woofers are also very close together. In fact, it would be identical to the ULSs (18" cabinet with 15" woofer). That would be kind of cool to have 4 15Hs stacked, one stack on each side... :D Guaranteed to blow out your windows! :p

This response was for the sub only. I suspect the dip is the room response at that location. The initial measurement graphs I posted had 1/6 octave smoothing, which masked the narrow dip at 60 Hz. This graph has no smoothing. Setting on sub: crossover out, phase 0, ULF trim 16 Hz.

I still think my current position is better than Alternate 1. Would you agree?

Without going the MBM route, and if the mid bass headroom is more important than the low bass headroom, yes. Not much 16 Hz organ pedals, yes.

BTW, where is this Alternate 1 location?

BTW, where is this Alternate 1 location?

If you look at the pictures of my listening room, Alternate Position 1 is on the left side of the room, under the window, approx 4 feet from the back wall. Because of the window, it would be difficult to stack the subs. And there is not room for all four subs there.

I doubt it can hit 130 dB at 10 Hz, but 115 dB, doable.

I'm pretty sure Not knows what he's doing with respect to measuring. This graph was *before* he got the clone amps too which he said added another 5-6db. Just saying.

http://i.imgur.com/G4tzt.png

That's also with the mic at the LP which was 12-13ft from the subs btw.

That's also with the mic at the LP which was 12-13ft from the subs btw.

Wow, that is pretty crazy output! A lot more output than I thought possible. What kind of measurement system is he using?

Wow, that is pretty crazy output! A lot more output than I thought possible. What kind of measurement system is he using?

I don't know the brand mic he's using off the top of my head but I know it's calibrated so that it's at least accurate down to his reading of 7hz. He's using REW to take the measurements I believe. Check out his build thread Doc I think you'll enjoy it. It's a good read.

http://www.avsforum.com/avs-vb/showthread.php?t=1314884

There's a couple guys on the DIY threads with systems capable of 115db+ at 10hz. Actually MKTheater has four CHT 18.2's with a clone amp and I'm sure he's able to achieve those levels as well. His room is smaller then most but still it's pretty impressive. Hopefully I'll get to hear it soon.:)

You do realize though this means your next sub needs to be capable of these levels? Maybe a ULS-18X2 in multiples?:D Your daughter IS out of the house now, leaving you plenty of time to come up with something to please all the bass-heads on these forums.;)

I don't know the brand mic he's using off the top of my head but I know it's calibrated so that it's at least accurate down to his reading of 7hz. He's using REW to take the measurements I believe. Check out his build thread Doc I think you'll enjoy it. It's a good read.

http://www.avsforum.com/avs-vb/showthread.php?t=1314884

There's a couple guys on the DIY threads with systems capable of 115db+ at 10hz. Actually MKTheater has four CHT 18.2's with a clone amp and I'm sure he's able to achieve those levels as well. His room is smaller then most but still it's pretty impressive. Hopefully I'll get to hear it soon.:)

You do realize though this means your next sub needs to be capable of these levels? Maybe a ULS-18X2 in multiples?:D Your daughter IS out of the house now, leaving you plenty of time to come up with something to please all the bass-heads on these forums.;)

While lots of people would love to dream about systems like that, not many would actually buy one! Shipping such BIG subs is also a big headache...:D

Isn't your real name Schwarzenegger?? :confused: Lifting the ULS should be a piece of cake! :eek: :D OK. We will stick to that location. Given that there are no other options regarding keeping doors open or closed, and the sub location is fixed, there is not much more I can help with :D. Just play around with the ULF Trim. Setting that to 50 Hz should give you a bit tighter bass. The ULF Trim frequency is where the bass starts to roll off GENTLY. The roll off rate is about 2 dB/Oct. So, even when set to 50 Hz, it's down only 4 dB at 15 Hz. The higher setting also gives you more headroom.

Q for you, Dr Hsu: I'm doing an Audyssey Pro calibration on a Denon 4311 with two HSU-15s. I've had the subs at the 16 hz trim and phase=0, which seemed to work - taking an AS-EQ1 curve literally - when I had a SC-57 and an AS-EQ1 in the past, in our 24 x 17 x 10 living room. However, on the "before" Pro certificate, I have a high room gain, starting at about 8 db relative to 75 db reference @ 20 Hz (Extreme left corner of the chart), and then decaying until it reaches a null at about - 5 db from 70 to 100 Hz, where it rises to almost 0, and flattens until I reach well over 100 Hz. The net result of this is that on the "After" chart, I don't get the -3 db point until well after 20 Hz (AustinJerrry: I hit -5 db after the second veritical line on the chart), and the predicted response hovers at -3 or -4 db after 100 Hz, where it flattens. Clearly my sub equalization isn't optimal.

I understand that the trim adjustment is 'gentle', but would moving the trim to 50 Hz flatten out the gain boost from the 16 Hz setting enough to give me better response overall in EQing the sub with Audyssey? Or am I better off looking at sub crawl and/or bass traps to doing something about this? If so, what would you suggest as traps?

FYI the subs are which are located on either side of our sofa, and within a foot of corners and a wall. I can't get too far into a true sub crawl without either running into WAF about placement, and/or well as structural limits to our room (like one wall being about 2" high and below a window on one side of our room, and the other side being semi-open to the hallway and dining area, and having a short mirrored wall with furniture). Having Mythos ST fronts, I don't think makes sense to have the subs up front (ST are set to small/80 Hz). Our room is also carpeted.

I probably should put this up on the Pro thread, but since my question is ULS-15 specific, thought I should give it a try here.

Thanks,
Stuart

Hey doc, ever thought about making a ULS-18? I'd love to see a sealed 18" from Hsu competitive in performance to the Velodyne DD18 but at a third of the price.

^^^ i actually asked that (http://www.avsforum.com/avs-vb/showpost.php?p=21721284&postcount=2077) already.

Q for you, Dr Hsu: I'm doing an Audyssey Pro calibration on a Denon 4311 with two HSU-15s. I've had the subs at the 16 hz trim and phase=0, which seemed to work - taking an AS-EQ1 curve literally - when I had a SC-57 and an AS-EQ1 in the past, in our 24 x 17 x 10 living room. However, on the "before" Pro certificate, I have a high room gain, starting at about 8 db relative to 75 db reference @ 20 Hz (Extreme left corner of the chart), and then decaying until it reaches a null at about - 5 db from 70 to 100 Hz, where it rises to almost 0, and flattens until I reach well over 100 Hz. The net result of this is that on the "After" chart, I don't get the -3 db point until well after 20 Hz (AustinJerrry: I hit -5 db after the second veritical line on the chart), and the predicted response hovers at -3 or -4 db after 100 Hz, where it flattens. Clearly my sub equalization isn't optimal.

I understand that the trim adjustment is 'gentle', but would moving the trim to 50 Hz flatten out the gain boost from the 16 Hz setting enough to give me better response overall in EQing the sub with Audyssey? Or am I better off looking at sub crawl and/or bass traps to doing something about this? If so, what would you suggest as traps?

FYI the subs are which are located on either side of our sofa, and within a foot of corners and a wall. I can't get too far into a true sub crawl without either running into WAF about placement, and/or well as structural limits to our room (like one wall being about 2" high and below a window on one side of our room, and the other side being semi-open to the hallway and dining area, and having a short mirrored wall with furniture). Having Mythos ST fronts, I don't think makes sense to have the subs up front (ST are set to small/80 Hz). Our room is also carpeted.

I probably should put this up on the Pro thread, but since my question is ULS-15 specific, thought I should give it a try here.

Thanks,
Stuart

I would set ULF Trim to 50 Hz, and do the subwoofer crawl. Place one sub at the listening location, woofer at ear level. Play and place the mic at the various possible sub locations. How deep is the room? Based on the response curve you got, you have great deep bass so I think your current location is good. I generally like the sub close by for better upper bass impact.

Hey doc, ever thought about making a ULS-18? I'd love to see a sealed 18" from Hsu competitive in performance to the Velodyne DD18 but at a third of the price.

That is a tall order! :eek:

I would set ULF Trim to 50 Hz, and do the subwoofer crawl. Place one sub at the listening location, woofer at ear level. Play and place the mic at the various possible sub locations. How deep is the room? Based on the response curve you got, you have great deep bass so I think your current location is good. I generally like the sub close by for better upper bass impact.

Thanks! I went to the dual subs to try to even the room out, and figured (based partially on reading the HSU forum and here) that the back of the room, flanking the MLP but with a little room from the wall, was my best bet over front or a diagonal sub placement, since I can't do parallel sides. The room's about 20 feet from the fronts to the MLP and the subs. I'm just trying to tame the low end to make the Pro correction less extreme, if that's possible, so that I might get a 1 or 2 db overall boost and a little more flatness, in the final Pro 'after' chart, if I also get some null improvement at 50-100 hz. I'll move the saga back to the Pro thread....any point, based on what I've said, in acoustic treatments?

As for sub haul--I can just see putting a ULS-15 beast on our leather sofa and listening... :eek:

That is a tall order! :eek:

But impossible? The DD18+ retails for $6k, but of course there is always room to bargain. But for $2k, it can be done via DIY very easily, something like a XXX Mealstrom or TC sounds 5400 Ultra, a 2 KW amp, an EQ, can all be had for less than $2k. Of course I wouldn't expect Hsu to try to compete with DIY price/performance ratio, but to equal the performance of a DD18 for under $2k, impossible? Also, forget all those features like onboard EQing and remote controls and a luxury finish, we are just talking about raw performance. Maybe it isn't possible, given the crazy state of the magnet market. All I'm saying is a ULS-18 would be THE BOMB!

But impossible? The DD18+ retails for $6k, but of course there is always room to bargain. But for $2k, it can be done via DIY very easily, something like a XXX Mealstrom or TC sounds 5400 Ultra, a 2 KW amp, an EQ, can all be had for less than $2k. Of course I wouldn't expect Hsu to try to compete with DIY price/performance ratio, but to equal the performance of a DD18 for under $2k, impossible? Also, forget all those features like onboard EQing and remote controls and a luxury finish, we are just talking about raw performance. Maybe it isn't possible, given the crazy state of the magnet market. All I'm saying is a ULS-18 would be THE BOMB!

We will see.... :D

to all quad drive owners, i have a couple of questions:

1. What kind of mains are you guys using with your quad drives?
2. What kind of woofers (and how many) do your mains have?
3. Have you guys ever crossed over as high as 120Hz to 150Hz?
4. What kind of response do you get when crossed that high?
5. How does it sound?

Dr.Hsu, here is a question for you.

I know you have spoken about headroom, so i was wondering, if you have a quad drive, it is obvious there is a lot more headroom, so as a result of that, could crossing over higher be a feasible option or is that defeating the purpose of headroom?

Kim, everything else being equal, I don't think adding a fourth ULS will give you a lot more headroom if you already have three ULSs, I am thinking less than 1 db, depending on placement. Placement can make a difference though, if your three are upfront, perhaps a fourth placed near-field will give you a real boost in headroom. If I am right, for one sub, adding another will give you a +3 db increase on output, adding one more on top of that will give you 1.5 db, and another will give you .75 db, but that would be for an anechoic chamber. My own home theater has four subs, the front two don't really do much but even out the FR somewhat, they add only about 2 db more headroom, but I will have to redo those measurements since I redid a couple things. In a four sub situation, you also have to be weary of cancellation, so keep checking playing with those phase switches to see how much is lost or gained.

Um Shady, you have Kimwyn confused with someone else. He only has a Dual Drive. Right now I think Jerry and myself have three each. You getting old buddy? :p

Oh, I though Kim was up to three now. Seems like all you guys are passing me by! Well, just wait until I win the lottery, I will get an octo-drive and then you guys will be sorry! Muhahaha!

Oh, I though Kim was up to three now. Seems like all you guys are passing me by! Well, just wait until I win the lottery, I will get an octo-drive and then you guys will be sorry! Muhahaha!

Yes! Two line source floor to ceiling stacks... :D:p

Dr.Hsu, did you see my question above?

Kim, everything else being equal, I don't think adding a fourth ULS will give you a lot more headroom if you already have three ULSs, I am thinking less than 1 db, depending on placement. Placement can make a difference though, if your three are upfront, perhaps a fourth placed near-field will give you a real boost in headroom. If I am right, for one sub, adding another will give you a +3 db increase on output, adding one more on top of that will give you 1.5 db, and another will give you .75 db, but that would be for an anechoic chamber. My own home theater has four subs, the front two don't really do much but even out the FR somewhat, they add only about 2 db more headroom, but I will have to redo those measurements since I redid a couple things. In a four sub situation, you also have to be weary of cancellation, so keep checking playing with those phase switches to see how much is lost or gained.

It is going to be room and placement dependent but here is an article showing some of the effects you are talking about with multiple subs. The db increase or decrease can vary dramatically based on frequency.

http://data-bass.com/data?page=content&id=80

And a graph showing the responses of 1,2,3 and 4 subs.

http://data-bass.com/images/content/80/G%2031510addingsubsto4.jpg

-Mike

Kim, everything else being equal, I don't think adding a fourth ULS will give you a lot more headroom if you already have three ULSs, I am thinking less than 1 db, depending on placement. Placement can make a difference though, if your three are upfront, perhaps a fourth placed near-field will give you a real boost in headroom. If I am right, for one sub, adding another will give you a +3 db increase on output, adding one more on top of that will give you 1.5 db, and another will give you .75 db, but that would be for an anechoic chamber. My own home theater has four subs, the front two don't really do much but even out the FR somewhat, they add only about 2 db more headroom, but I will have to redo those measurements since I redid a couple things. In a four sub situation, you also have to be weary of cancellation, so keep checking playing with those phase switches to see how much is lost or gained.

One of my 4 took a different delivery route and was a day or so later arriving than the first 3. There was a very definate and noticeable difference when the fourth one was turned on - the WOW factor went up a notch or two. Can't say if freq response was different, because I waited until #4 came in before running REW. Smoothing of the FR was likely what I heard.

Then a few months ago one of the ULS amps failed. Even at low volume, I could tell something was wrong. When I saw one of the amp LEDs was off, I knew what had happened. BTW, Pete helped me get the amp repaired quickly.

As always YMMV with diferent rooms, setups, etc.

Kimwyn: Think I told you before, but my mains are Klipschorns with a Belle Klipsch center. After running Audyssey Pro, I tried leaving the mains as large vs. crossing over at 80. Really could not tell that much difference, but left them as well as the rest of the channels crossed at 80. Pete has said that he has used up to 120 or so with the ULSs with good success, but I have never tried that high.

Dr HSU,

congratulations on the excellent review of the VF15 by the Widescreen Magazine. I have a 22.5'x17'x9' 7.2 dedicated home theater. I am using two REL Stadium II for subs and have tried multiple combinations within my room, but I am never satifisfied. Bass is boomy and under taxing conditions they have a tendency to distort. I originally bought them beacuse I wanted to do some critical two channel listening...but now all I am interested in is home theater application. Question: which product would you recommend or my room? Can I perhaps get away with two ULS-15? Do you think I may be able to mix my two RELs with two ULS-15 to get the benefit of four subs?
Thanks in advance

After running Audyssey Pro, I tried leaving the mains as large vs. crossing over at 80. Really could not tell that much difference, but left them as well as the rest of the channels crossed at 80. Pete has said that he has used up to 120 or so with the ULSs with good success, but I have never tried that high.

This is interesting. With the main speakers set to large, no bass frequencies are directed to the subs. The only signal the subs will reproduce is what is in the .1 channel, which doesn't contain content that often. So are you saying that you couldn't tell much difference with the subs on or off? Or are you using "double bass"?

Dr HSU,
...but now all I am interested in is home theater application.

Get two VTF-15's instead of ULS'. Just my 2¢.
Tim

This is interesting. With the main speakers set to large, no bass frequencies are directed to the subs. The only signal the subs will reproduce is what is in the .1 channel, which doesn't contain content that often. So are you saying that you couldn't tell much difference with the subs on or off? Or are you using "double bass"?

AVR has sub outputs set to LFE+MAIN, so yes, the subs are active with the mains set to large. And, oh yes, there is a difference with the subs on - HUGE:D

AVR has sub outputs set to LFE+MAIN, so yes, the subs are active with the mains set to large. And, oh yes, there is a difference with the subs on - HUGE:D

Thanks for clarifying.

to all quad drive owners, i have a couple of questions:

1. What kind of mains are you guys using with your quad drives?
2. What kind of woofers (and how many) do your mains have?
3. Have you guys ever crossed over as high as 120Hz to 150Hz?
4. What kind of response do you get when crossed that high?
5. How does it sound?

Dr.Hsu, here is a question for you.

I know you have spoken about headroom, so i was wondering, if you have a quad drive, it is obvious there is a lot more headroom, so as a result of that, could crossing over higher be a feasible option or is that defeating the purpose of headroom?

Sorry! Missed your question to me. You can cross over higher, but that makes the sub localizable. Crossing over above 80 Hz makes the sub localizable. If you have three ULSs, you will get more headroom to add a MBM and crossover at 50 Hz between the ULSs aand the MBM, than getting another ULS. As ShadyJ said, adding one sub to three will not give you a whole lot more headroom. Adding a MBM on the other hand can potentially add quite a bit more headroom, and is cheaper. (I would rather you buy the ULS - I will make more money.. :p).

Dr HSU,

congratulations on the excellent review of the VF15 by the Widescreen Magazine. I have a 22.5'x17'x9' 7.2 dedicated home theater. I am using two REL Stadium II for subs and have tried multiple combinations within my room, but I am never satifisfied. Bass is boomy and under taxing conditions they have a tendency to distort. I originally bought them beacuse I wanted to do some critical two channel listening...but now all I am interested in is home theater application. Question: which product would you recommend or my room? Can I perhaps get away with two ULS-15? Do you think I may be able to mix my two RELs with two ULS-15 to get the benefit of four subs?
Thanks in advance

Thank you for your compliments! Actually, that was a review of the VTF-3 MK4, not VTF-15H. :D For HT application, two 15H would be even better. I would just use the 15Hs. The REL has much lower headroom, so they will distort badly before the 15H reach their limits. I will use them in another room, or sell them and use that to help pay for the 15Hs.

I was afraid of that...I will get rid of the RELs. The only other question for my room (4000 cuft) is how many 15Hs...2 vs 4??? Money is really not too much of an issue, altough I'd rather not through money away..:)

I was afraid of that...I will get rid of the RELs. The only other question for my room (4000 cuft) is how many 15Hs...2 vs 4??? Money is really not too much of an issue, although I'd rather not through money away..:)

You can never have too much subwoofer. When you have more, you get lower distortion and more headroom. Bass sounds more effortless, and dynamic. Also, the long term reliability improves as each sub needs less power to play at the same level.

Can you post a detailed sketch of your room and adjoining rooms? Sometimes leaving the door to adjoining rooms open can give you better deep bass.

I got the ULS 15 and it's been amazing. I was doing the audessey sub level tone and it was rattling my windows. Sounds amazing and the fit and finish are great. It doesn't fit in my end table so I'll have to wait till I can get a bigger end table so I can put the sub nearfield. I have it between my right speaker and the TV so it's close to my corner at 50 hz trim. I was looking into getting a mic and was wondering if anyone had any suggestions. I'd like it to work well at bass frequency. I was thinking of something like this:

http://cross-spectrum.com/measurement/calibrated_behringer.html

It says when it's calibrated it's accurate 5-25khz so that should be all I need and it sounds good to have a calibration file for my specific mic but I'm open to other suggestions. I'm also fine with more expensive mics if there are good reasons for it this one just seemed to have a good balance of price/performance.

I got the ULS 15 and it's been amazing. I was doing the audessey sub level tone and it was rattling my windows. Sounds amazing and the fit and finish are great. It doesn't fit in my end table so I'll have to wait till I can get a bigger end table so I can put the sub nearfield. I have it between my right speaker and the TV so it's close to my corner at 50 hz trim. I was looking into getting a mic and was wondering if anyone had any suggestions. I'd like it to work well at bass frequency. I was thinking of something like this:

http://cross-spectrum.com/measurement/calibrated_behringer.html

It says when it's calibrated it's accurate 5-25khz so that should be all I need and it sounds good to have a calibration file for my specific mic but I'm open to other suggestions. I'm also fine with more expensive mics if there are good reasons for it this one just seemed to have a good balance of price/performance.

Glad you liked our ULS! Enjoy it and welcome to the Hsu family!

If that mic gives you an accurate calibration, go for it!

I got the ULS 15 and it's been amazing. I was doing the audessey sub level tone and it was rattling my windows. Sounds amazing and the fit and finish are great. It doesn't fit in my end table so I'll have to wait till I can get a bigger end table so I can put the sub nearfield. I have it between my right speaker and the TV so it's close to my corner at 50 hz trim. I was looking into getting a mic and was wondering if anyone had any suggestions. I'd like it to work well at bass frequency. I was thinking of something like this:

http://cross-spectrum.com/measurement/calibrated_behringer.html

It says when it's calibrated it's accurate 5-25khz so that should be all I need and it sounds good to have a calibration file for my specific mic but I'm open to other suggestions. I'm also fine with more expensive mics if there are good reasons for it this one just seemed to have a good balance of price/performance.

I have the Cross Spectrum calibrated Behringer mic and it works well with REW; just be sure to apply the calibration file to whatever measuring software you use.

the fit and finish are great.

My Quads are in walnut - beautiful. Then I bought a satin black for use in another room and was completely floored at how good the "plain" finish looks.

Dr. Hsu - I don't know who makes your enclosures, but keep them happy!:D

You can never have too much subwoofer. When you have more, you get lower distortion and more headroom. Bass sounds more effortless, and dynamic. Also, the long term reliability improves as each sub needs less power to play at the same level.

Can you post a detailed sketch of your room and adjoining rooms? Sometimes leaving the door to adjoining rooms open can give you better deep bass.

Room layout is straigth forward 4000 cuft, dedicated HT room. One door which opens to a corridor/stair landing. Perhaps I shold start with two 15hs amd see how it goes? Pleases note present location of my RELs. Where would you locate the 15hs?

My Quads are in walnut - beautiful. Then I bought a satin black for use in another room and was completely floored at how good the "plain" finish looks.

Dr. Hsu - I don't know who makes your enclosures, but keep them happy!:D

Thank you! We will try to keep them happy. :)

Room layout is straigth forward 4000 cuft, dedicated HT room. One door which opens to a corridor/stair landing. Perhaps I shold start with two 15hs amd see how it goes? Pleases note present location of my RELs. Where would you locate the 15hs?

How far are your ears from the front wall when seated? Can you sketch in the corridor and stair landing? If you are sitting in the middle of your room, you will not get great deep bass there. That is where the deep bass null is. If you can sit further back, say 2 - 3 ft off the back wall, deep bass will be much better. Also, leaving the door on your left open will also improve deep bass.

If you have great flexibility in setting up this room, try moving the seat to about 3 ft out from the back wall, and try placing the two subs at the 1/3 positions along the back wall - about 5 ft from the side walls.

Yes, start out with two 15Hs. :D

How far are your ears from the front wall when seated? Can you sketch in the corridor and stair landing? If you are sitting in the middle of your room, you will not get great deep bass there. That is where the deep bass null is. If you can sit further back, say 2 - 3 ft off the back wall, deep bass will be much better. Also, leaving the door on your left open will also improve deep bass.

If you have great flexibility in setting up this room, try moving the seat to about 3 ft out from the back wall, and try placing the two subs at the 1/3 positions along the back wall - about 5 ft from the side walls.

Yes, start out with two 15Hs. :D

And if you have a setup like that last one, what do you do when midbass is hitting a dip if not a null in that room, hypothetically speaking? And you have Audyssey....