Official HSU ULS-15 Thread - Page 85

I applaud you for all your efforts! One easy way to lower the gain on the subs equally without having to move them again is to do the following (this works only if they have been gain matched before):

1. Play the subs one at a time. For each sub:

a. Place mic 1 ft in front of sub (distance not critical).

b. Play a 40 Hz tone (not critical what frequency - 50 Hz or 32 Hz will work as well).

c. Adjust your processor to get 80 dB reading.

d. Turn down (or up) the number of dB you want (in your case, down 5 dB).

It does not matter that the subs are in different locations. When they have already been gain matched, adjusting each one down the same amount means they will still be gain matched. As long as the mic stays in the same position when you are adjusting the gain for that sub, you are in good shape.

One thing to try - try running Audyssey with just the rear subs turns on, versus with just the front subs turned on. If Audyssey still set the gain 9.5 dB lower for the fronts, no point having the subs up front. Put all four behind you.

 

Great post, Jerry! And an awesomely flat response!! 

Thank you for the interesting recommendations, Dr. Hsu! I wasn't looking forward to moving the subs again. The subs actually sound pretty good the way they are now.

Jerry

Thanks, Keith. Now on to the next project. 4K displays, anyone?

But because Audyssey is not able to consider how the confluence of subs may improve the modal issues, something may well be lost in removing the subs from the front. One would have to evaluate the responses of the front/rear setup, as measured in a few different seats, and compare that to the rear-only subs case.

It is not really necessary to move the front subs to the rear to get a good insight into the difference, since the rear subs would be essentially co-located. Just compare the 4 subs as they are against using only the two rear subs. If the response variation across the seats is reduced with the fronts active, that would justify leaving them there.

BTW, it is not necessary to run a separate Audyssey pass with the rear-only subs, since Audyssey on/off makes no difference in seat-to-seat response variation. No need to mess up the settings. That is only going to be necessary if you change the speaker locations.

Very good suggestions, Roger. I plan on taking some additional measurements tomorrow. I will measure rear subs only. I will also measure taking the 10dB difference between the front and back trims, halving it, and adjusting the trims. Not sure how this will affect the response, but it is worth a measurement.

So you resisted the siren's call of the Submersives... I'm impressed...

Just to be clear, the overall response is not the interesting topic. It is how the response differs from one place to another. If they are all lumpy, in exactly the same way, EQ can easily fix it. But if each location is vastly different. EQ cannot alter those differences. So the goal of multiple subs is uniformity, then let the EQ do its thing. Based on Welti's findings, uniformity is improved when the woofers are properly distributed.

To measure this uniformity thing you'll have to overlay the responses and see how much they differ.

In my understanding, the cross modal cancellations Welti describes happen when the subs contribute equal energy in a symmetrical layout. It should not matter that when you sit closer to some they sound louder. But that's theory. If altering the balance improves the results, then no reason not to do it.
Edited by Roger Dressler - 12/14/12 at 12:04pm

and the ULS-15 thread is once again interesting....i love it!!!!

Like to hear of people going to the ultimate (4) level with these subwoofers with great data. I will not allow myself to succumb to adding more lol!!!

 

Roger,

 

Here is an 8-position measurement of the bass, using the same positions as for the Audyssey calibration, with no smoothing. I am measuring all four subs in the configuration described in my earlier post.

 

IMO, the response looks reasonably smooth position-to-position, especially below 100Hz.  I am inclined to leave things the way they are for now, and give myself some time to get accustomed to the current configuration.  Your thoughts?

 

While it is a little hard to see at 10 dB/div, I see nothing alarming. Perhaps your multi-sub setup is working Welti already! And if so, I wouldn't mess with it.

If you feel like probing what happens with just the rear subs working. Just kill the fronts and take the same set of measurements. (This is when having 8 mics and a multiplexer gets real handy!) And put them all in the same plot. If it is REW, anyway, as then you could post the REW file and it would be easier to examine.

What are the response like for each sub one sub at a time?

Sorry, Dr. Hsu, I did not take those measurements.  I will make a note to capture this data next time I am running REW measurements. 

No hurry. post when convenient.

I have made progress with the integration of the fourth ULS-15.  In a previous post, I described how I am having trouble with the trims that Audyssey has been setting for the subs.  The two front subs have a trim of +7.5, and the two rear, co-located subs have a trim of -3.5.  The 11dB difference has been bothering me, and the overall quality of the bass seems lacking, even though the frequency response is acceptably flat.

 

The more I thought about it, I began questioning the gain-matching approach I have been using.  I decided to try a different approach:  treat the two co-located rear subs as "one virtual sub".  Compare the two ULS-15's with a single Seaton Submersive, which has two opposing sealed 15-inch drivers in one cabinet.  If I were gain-matching the Submersive to the two front ULS-15's, the current gain on the front subs would actually be 6db too low.  Co-locating the two ULS-15's raises the output level by approximately 6dB, so if you were to consider this a one "virtual sub", then it is really no longer gain-matched with the two front subs.  To re-establish the gain-matching, I raised the gains on each of the two front subs by 6dB so that their output more closely matches the rear "virtual sub".

 

Now, when I run the Audyssey calibration, the front trims are set to -.5dB, and the rear "virtual sub" trim is set to -3dB.  Since the rear subs closer at only 3.5 feet from the MLP, compared with the front subs at 11 feet, this result is much more consistent with what I had been expecting.  The frequency response graph is also virtually unchanged.

 

I haven't thought through what this different approach means to the combined headroom of the four subs, but I do hear a difference in how the bass sounds, and the difference is very positive.  I would describe the current sound as more enveloping, smoother, and stronger.  Now I need to run through my go-to demo material to confirm this initial impression, but my feelings are very positive.

So, are the volume setting on all four subs such that they are all gain matched now? Yes, I would consider the two front ones as 'one virtual sub' and the two rear ones another 'one virtual sub'. If all four are now driven to about the same power, they should all reach the limit at about the same time versus previously two sub driven to the limit much earlier than the other two. Should certainly sound more effortless and dynamic now.

I am not sure we are on the same page. Let me describe it a different way.

The two back subs are gain-matched with each other, at a setting of 85dB. When placed together, the combined output measures 90dB. The front two subs, which are ten feet apart, are also gain-matched with each other, but at a higher level of 90dB. So I have "three" subs, the two in front, and the "virtual sub" in the rear, and all three are outputting at 90db.

Where did you have the mic when you measured those SPL? From your listening chair with each sub at their current location?

No, with the mic 1" in front of the dust cap. For the co-located subs, half-way between them, 1" in front.

^^ It means the front subs will run out of steam before the rears. That's not necessarily bad when there's sufficient steam on tap. Especially if you like the quality better.

 

That is true, Roger.  I think how I assess bass performance may be somewhat different from many of the people I run into in the subwoofer threads.  I look at three things, in the following order:

 

- Measurements.  I try and use whatever techniques I know, and follow the good advice of many here on AVS, to get the best measurements (frequency, waterfalls).  If the measurements aren't good, I'm not happy.

 

- Musicality.  I value good bass performance when listening to music much higher than when watching movies.  If the bass isn't musical, I haven't achieved my objective.  I haven't heard musical bass that doesn't sound great with movies as well.  I just listened to one of my "go-to" recordings, Diana Krall Live in Paris (Dolby Digital 5.1 DVD).  John Clayton's upright bass on tracks like "All or Nothing" and "Let's Fall in Love" sounded sublime.

 

- Headroom.  This is lowest on my list because I don't tend to listen to movies at high volume levels.  Reference is way too loud for my comfort.  Of course, it is important to be able to listen at reasonable levels without distortion or bottoming out, but for me "loud" is probably around -10 on my MV.  With my current configuration, there is enough headroom to go louder than that.  Of course, if I had a wonderful HT like your "Deadwood Theater", I might listen at louder levels!  ;)

 

Thanks for your valued feedback.

Yes. It is quite possible. Next to the sub itself, the room in which you listen is the biggest contributor to the overall sound you hear. In fact, many (myself included) would argue that the room is the biggest factor - a far bigger factor than the equipment. After years of pro sound experience, I can tell you that my PA systems sound very different from one venue to another - and that is entirely a factor of room acoustics and speaker placement as the gear is identical.

However, it could just as easily be listener bias. You are so used to how your Sunfire sounds that anything else is going to sound radically different. But is different worse or better? That's much harder to quantify. I have learned this from pro sound experience as well. When I insert a new piece of gear into an established system, I have to give it some time - time for my ears to adjust to the difference. The best example I can think of is when I made the move from analog to digital mixers. At first, I really didn't like what I was hearing. But now, I wouldn't go back to analog for anything. Why? Because I have learned how to get the best from the digital boards. And once you learn your way around them, they clearly provide superior sound and flexibility in a live setting.

So what am I saying? Give it some time. Most companies have a generous return policy. After lengthy listening, if you still don't like how it sounds, send it back. Sound is all about color and all equipment colors sound is some way or another. It may well be that you prefer what the Sunfire does to sound. But I would allow myself some time to adjust to the sound (as well as doing some tweaking as hometheatergeek suggested) before shipping it back.

^^^^ is that supposed to be in this thread???? I am sure he was using a mobile device when that happened.......damn mobile devices!!!!!! LOL

I am running a very similar setup, colocated Vtf's and two PC Ultras. I've gone through the same exercise but used 75db as the end point since I am running audyssey. Is this correct?

Unfortunately, the situation is different for different listening rooms and subs. If you have Audyssey XT32 with two sub channels, then I assume you place the VTF's on one sub channel, connected with a Y-cable. The two PC Ultras would go on the second sub channel, also connected with a Y-cable. Since the VTF's are co-located, you are likely getting a 6dB boost. Same for the PC Ultra's, if they are co-located. Starting off, each sub pair should be gain-matched. Place an SPL meter an inch in front of the sub's dust cap, play the AVR's sub channel test tone (make sure the trim on the AVR for that channel is set to zero), and make sure all other subs are turned off. Adjust the gain on the back of the sub until it is equal to 90dB (which I have found is a good starting point when gain-matching). Use 85dB for the subs that are co-located. Do the same for the other matching sub, and then for the other two subs. So you now have two sub pairs, and the subs within each pair are gain-matched.

Now run the Audyssey calibration. If you have XT32, you will be presented with a sub level-matching screen. You can observe the sub levels, but don't change them. Typically, I find the levels on this screen to be lower than 75dB, which is not a concern, because Audyssey will set the trims to the correct value as it runs the calibration. When the calibration has completed, check the trims on the two sub channels. Ideally, they should be reasonably close to each other (within 4-5 dB is OK). If either channel is at the channel max or min (+12 or -12), this is not good, and you will need to go back to the gain-matching step and adjust the gain for those two subs either up or down to correct the issue.

It is also desirable to have the two subs that are on a single sub channel placed so they are equidistant from the MLP.

If you have MultEQ XT, and not XT32, then my recommendations are not applicable. Optimizing four subs on an AVR with only XT is much more complicated.

Good luck!
Edited by AustinJerry - 1/1/13 at 9:07pm

I have a dual drive ULS but I'm considering moving to DIY subs b/c of my screen wall rebuild. I love the HSU and I have tons of output, but b/c of my kids .. I'm considering building something that is different dimensions than the larger retangular box. Anyone else ever ventured into this area? I would move the ULS to the family room but the wife says one room full of speakers is enough

I am currently using a Klipsch RW-12D. I am looking for a subwoofer that will go deeper. My living room is about 1800 cu-ft. However, since the living room opens up to a hallway that leads to the dining room and kitchen, the total space is close to 5000 cu-ft. I know I would need ported subwoofer and/or dual subwoofers. However, due to space limitation and WAF, I am limited to one subwoofer that is not that much bigger than the RW-12D. So, I am considering the Hsu ULS-15 due to its size and wireless capability. If anyone is running just one ULS-15 in a large space, would you share your experience? Thanks.

u need a compact sub

jl112 may fit yr waf and size