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One better sub or two subs - Page 14

post #391 of 757
Quote:
Originally Posted by braveheart123 View Post

First of all, Audyssey does not suggest/set crossover for any speaker. It just returns the -3dB point to AVR. AVR, in fact, sets crossover frequencies for all the speakers.

As to the lowering of crossover frequency; what I meant was Audyssey employs more filters to correct subwoofer response than it does for the mains and the rest of the speakers. If one crosses the mains lower than e.g. 90Hz that is set by avr to e.g. 70Hz after audyssey calibration, that is not good. As speakers will take over from sub from 70Hz and audyssey applies less filters for speakers' correction as opposed to the the same signal going to the sub where more filters are employed for response correction.

Huh? That's just a bunch of incoherent gibberish.

"First of all," we both described the phenomenon as Audyssey's setting, finding, recommending, etc., a crossover point. You know what I mean by that and I know what you mean. Don't pretend to get distracted by something so trivial, after all you described it in the same way, as did Craig. It's an irrelevant difference here anyway, why even mention it?

Regardless, the reason why you shouldn't lower the crossover set during Audyssey calibration, as Craig said and I said, and as is the opposite of what you said, is because it doesn't properly correct response below the crossover point.

It is not, as you are now weirdly saying, because it applies "more filters" to the LFE channel than to the other channels. It simply doesn't try to filter _the loudspeakers_ for a response it doesn't hear (i.e., a lower crossover point than the speakers can actually support at the listening positions). So if you lower the crossover after Audyssey calibration, a portion of your loudspeaker response will go unfiltered.

That's why.

Edit: ...and I'd like to apologize for being so confrontational. Sorry, I was cranky; I had not yet had my snack.
Edited by SaviorMachine - 10/9/13 at 8:38am
post #392 of 757
Its ok grumpy we all have our moments... tongue.gif
post #393 of 757
Yeah, right? Big ups to Braveheart for doing his damnedest to help new HT fans find their legs, it's more than I've done.
post #394 of 757
Quote:
Huh? That's just a bunch of incoherent gibberish.

You better have a chat with Chris Kyriakakis. Shoot him an email or chat with him on Ask Audyssey.
post #395 of 757
Quote:
Originally Posted by braveheart123 View Post

First of all, Audyssey does not suggest/set crossover for any speaker. It just returns the -3dB point to AVR. AVR, in fact, sets crossover frequencies for all the speakers.
This is correct. However, AVR manufacturers have "evolved" and adopted Audyssey's suggested crossover strategy. At one time, almost all AVR's set any speaker with a <80 Hz -3 dB point to "Large." Audyssey's recommended practice was for the user to override that setting and invoke crossovers on the main channels. When the speakers were re-set to "Small" the first crossover that was selected was always the next available crossover above the -3 dB point of the speakers. Over time, Audyssey has gotten AVR manufacturers to change their decision-making, and be more appropriate in their crossover and speaker size selections. It's still the manufacturer's decision, but they are making better decisions these days.
Quote:
Originally Posted by braveheart123 View Post

As to the lowering of crossover frequency; what I meant was Audyssey employs more filters to correct subwoofer response than it does for the mains and the rest of the speakers. If one crosses the mains lower than e.g. 90Hz that is set by avr to e.g. 70Hz after audyssey calibration, that is not good. As speakers will take over from sub from 70Hz and audyssey applies less filters for speakers' correction as opposed to the the same signal going to the sub where more filters are employed for response correction.
This is also correct, but this recommendation really applied more to raising low crossovers, (40, 50, 60 Hz), up to 80 Hz. That way more bass info from the main channels was sent to the subwoofer channel, were it was also corrected with the higher resolution filter taps. Of course, it really only applied to MultEQ and MultEQ XT versions of Audyssey that had lower numbers of filter taps for the main channels than for the subwoofer channel. With the introduction of XT32, this is no longer an issue. All the channels in XT32 now have the same filter tap resolution:
http://www.audyssey.com/technologies/multeq/flavors
Of course, you don't want to raise low crossovers up to a point where the sub becomes localizable, so 80 Hz is about the limit for this recommendation.

Craig
post #396 of 757
Quote:
Yeah, right? Big ups to Braveheart for doing his damnedest to help new HT fans find their legs, it's more than I've done.

Very inappropriate remarks....
post #397 of 757
Quote:
Originally Posted by braveheart123 View Post

As to the lowering of crossover frequency; what I meant was Audyssey employs more filters to correct subwoofer response than it does for the mains and the rest of the speakers.
OK, that's a better way to describe the version of Audyssey in the OP's receiver than your earlier comment that "audyssey applies more filters the lower you go in the spectrum (bass frequencies)". What you described earlier is true for XT32 but not for previous versions (which distributed filters evenly across the spectrum).
Quote:
Originally Posted by braveheart123 View Post

If one crosses the mains lower than e.g. 90Hz that is set by avr to e.g. 70Hz after audyssey calibration, that is not good. As speakers will take over from sub from 70Hz and audyssey applies less filters for speakers' correction as opposed to the the same signal going to the sub where more filters are employed for response correction.
If you manually lower the crossover point from 90Hz to 70Hz, you aren't giving up "more filters" for "less filters", you're giving up corrected response for uncorrected response (no filters), because Audyssey won't have corrected below 90Hz in the speakers.
post #398 of 757
Thread Starter 
post #399 of 757
Quote:
Originally Posted by braveheart123 View Post

Quote:
Yeah, right? Big ups to Braveheart for doing his damnedest to help new HT fans find their legs, it's more than I've done.

Very inappropriate remarks....
Re-read the remark. He was paying you a compliment (for giving it your all to help a newbie).
post #400 of 757
Quote:
Originally Posted by sdurani View Post

Re-read the remark. He was paying you a compliment (for giving it your all to help a newbie).

That's what I thought also. Just goes to show you once a certain mode sets in things are easy to misinterpret.
post #401 of 757
I know; but I also know the context he was saying that in. You know the preamble.
post #402 of 757
I have a chance to get two subs at a good price but they are different brands, will that have much affect? I want to put one up from and the other behind me or closer to my seating distance
post #403 of 757
Quote:
Originally Posted by blee0120 View Post

I have a chance to get two subs at a good price but they are different brands, will that have much affect? I want to put one up from and the other behind me or closer to my seating distance

What subs are they?
post #404 of 757
Quote:
Originally Posted by blee0120 View Post

I have a chance to get two subs at a good price but they are different brands, will that have much affect? I want to put one up from and the other behind me or closer to my seating distance
You'll get more and better responses if you start your own thread with a title specific to your issues.

Craig
post #405 of 757
Quote:
Originally Posted by craig john View Post

You'll get more and better responses if you start your own thread with a title specific to your issues.

Craig

+1

Let the OP keep his thread on track. smile.gif
post #406 of 757
Quote:
Originally Posted by blee0120 View Post

I have a chance to get two subs at a good price but they are different brands, will that have much affect? I want to put one up from and the other behind me or closer to my seating distance

Best is to have identical subs. Reason being two different subs have different amps with different gain structure. One my run out of steam at some point during playback while other may still be galloping along. And that's not all; there are many other issues with running different subs together. But having said that, I and many other members here have successfully done it.

Like others have suggested; best would be to start your own thread. You will be best served there. smile.gif
post #407 of 757
Thread Starter 
Quote:
Originally Posted by braveheart123 View Post

Best is to have identical subs. Reason being two different subs have different amps with different gain structure. One my run out of steam at some point during playback while other may still be galloping along. And that's not all; there are many other issues with running different subs together. But having said that, I and many other members here have successfully done it.

Like others have suggested; best would be to start your own thread. You will be best served there. smile.gif

Well we tried it as well but its not that simple. I"m very sure its doable. Specially if you have REW. It made everything much easier. My advice to anybody out there following this thread and is a beginner like me trying to setup a good home threater is to invest into buying equimpent for REW. REW is not necessary if you prefer another software as long as it is as simple as REW (and free as well).

I was trying to find best place for subs and it was a very lengthy process and REW cut that process from 20 mins to 10 seconds. And its not just time. I had to carry my laptop around and constantly look at SPL to get reading and plug into excel sheet.

So do youself this big favor and get the equipments to work with REW.
post #408 of 757
Thread Starter 
In 2nd last post, I mentioned this link
http://www.avsforum.com/t/1494052/acoustics-101-with-anthony-grimani

I don't know if any of you had a chance to view it but I found it very informative. The whole episode is about room correction. Here are the main points that I took out of it

1 - Treat room with 20% Side,Top and Rear walls with absorbtion panels. Note that front wall is not included
2 - Treat room with 20-25% Side,Top and rear walls with diffuser panels. On top its preferred to have diffuser a little behind MLP.
3 - Bass traps in corners.

They also showed an image if you want bare mimium correction which includes all three but in main spots. According to them, it will fix around 80-90% of issues. The main areas included Bass traps and early reflection points and diffusers at MPL. (can't exactly remember but I will draw an image and post later).

For Bass trap, they did mention that it is very hard to have them absorb low frequencies but they do have one that does and absorbs as low as 30 hz but you can imagine the price they are charging :-). So my question now is if its worth buying those? There is DIY option as well but what are the odds we can do it as eaisly as absorbtion panels? Does the outcome superseeds the price (assuming it'll cost around 1200.00)?

I think Craig has good knowledge on it. Craig?????????????? or anybody else ?????
post #409 of 757
I'd say you should visit some home cinemas or HT setups that have room treatments done and experience it yourself. I have, and it is day/night difference. An average system sounds amazing and an amazing one sounds out of the world IMO.
post #410 of 757
Quote:
Well we tried it as well but its not that simple.

Yes but you simply discarded near-filed placement option.
post #411 of 757
Thread Starter 
Quote:
Originally Posted by braveheart123 View Post

Yes but you simply discarded near-filed placement option.
ah yes and near field will bypass all room acoustic issues. Good point.
post #412 of 757
Thread Starter 
Quote:
Originally Posted by braveheart123 View Post

I'd say you should visit some home cinemas or HT setups that have room treatments done and experience it yourself. I have, and it is day/night difference. An average system sounds amazing and an amazing one sounds out of the world IMO.

Interesting. This brings two issues.
1 - Finding home cinemas
2 - Letting them let me see their home cinemas.

People are not always comfortable unless they know you. Yes that'd definitely show the difference but then the very cinema could have been build up from ground to keep in mind that it will be used as a theater. In my case, it was a bassment previous owner built and I converted it into a long room (only keeping projector in mind) and then later realized that sound is a MAJOR part of home theater. So even if someone's home theater sounds great doesn't mean mine will as well if I were to have same room correction. Room shape also plays an important role and the fact that my room is open from one side makes it even worse :-(.

I"m very sure that room correction will play a good role. My point was more towards Bass traps. What value will they add? What's the before and after effect change with Bass Traps. I understand that they eliminate the standing waves but what I don't know what happens to listening when there are standing waves VS standing waves eliminated using Bass traps.
post #413 of 757
Quote:
I understand that they eliminate the standing waves but what I don't know what happens to listening when there are standing waves VS standing waves eliminated using Bass traps.

Fuller bass response. You will find more detail in LFE and redirected bass. It will be clearer and cleaner.
post #414 of 757
Quote:
Originally Posted by SherazNJ View Post

My point was more towards Bass traps. What value will they add?
Bass traps, like any absorption, can help reduce decay times. When certain frequencies linger for extended periods of time, they can mask details higher up in the frequency range. By lessening the overhang at these problem frequencies, upper bass as well as mid/high frequency details are often unmasked and easier to hear.
post #415 of 757
Quote:
Originally Posted by sdurani View Post

Bass traps, like any absorption, can help reduce decay times. When certain frequencies linger for extended periods of time, they can mask details higher up in the frequency range. By lessening the overhang at these problem frequencies, upper bass as well as mid/high frequency details are often unmasked and easier to hear.

You will see that difference in your waterfall graph (the base of the mountain will stick out less ;)).

post #416 of 757
Thread Starter 
The purpose of this post is to summarize the whole process. I'll also post the final results we had. I had the pleasure to meet Josh Craig. He was kind enough to take some time (whole day in fact) from his busy schedule to pay me a visit. We had a few expresso and some cheesecake and then we started working on the theater.

Right away he pointed out how far I was sitting from screen. I was compromising screen size for sound. So we decided to find best spot for screen and then see if we can find it best for sound as well. So we moved around 13 feet away from screen. This definitely made screen look a lot bigger as compared to before. Doing so also made front and central speaker sound much better. Craig then noticed that for some reason, speakers didn't sound as sharp as they should. Playing around with avr settings, we found out that Home Theater EQ option was doing that. So we turned that off. Now the speakers sounded as we wanted them to.

Next was to figure out best spot for subs. It took craig on two tries to find the best spots :-). We moved one sub 5 feet to the frong from MLP in the hugging Left wall and other 5 feet to back from MPL hugging right wall. Basically both subs are at equal distances from MPL. We ddin't have to change phase at all to get good frequency readings. Here are two graphs that shows final results (after running Audyssey).





Everything sounded very well. Later after Craig left, I realized that my subs sounded better before. It was a mistake on my part becasue in previous positions, I was running subs hot. Anyway, I moved subs back to where they were and realized that reading wasn't as good and it didn't sound same until I turned gain know up and sub trim. That made me realized that craig did choose best spot in the first place. So I moved them back and turn gain know to 2 p.m.

Now everything sounds great. My only concern (yeah they never end) is that rear speakers are way too far from the rest of speakers. They sound ok but I think I'm just going to increase them a bit in avr. Also surround speakers are at 8 feet hight and are pointing straight instead of pointing to MPL. I don't konw how much of a difference this will make. But, later on I'll change surround with Bi-polar surround speakers.

So sum the whole process up, I'd recommened to who ever is reading this post and trying to setup home theater to do the following

1 - don't sacrifice one part of your threater completely for another. If you are in plan mode, try to give sound and video equal attention. If either part is weak, your theater will be missing a lot.
2 - Don't only rely on your ears. Take measurements.
3 - Buy USB microphone and download REW (or use any other software that does the same). Don't waste time on using onlly Radioshack SPL. It is doable but very time consuming. Comparing cost of buying microphone vs effort of only using SPL to take reading, cost is much cheaper.
4 - Don't be afraid of using REW. Don't think its a big learning curve. It is not. If you have usb mice, its a piece of cake to get going. Use this guide http://www.avsforum.com/t/1449924/simplified-rew-setup-and-use-usb-mic-hdmi-connection-including-measurement-techniques-and-how-to-interpret-graphs/270#post_22823463. Use Frequence graph to check peaks and nulls and eliminate them by moving subs around. Read previuos posts to get ideas. There are many posts on that here :-)
4 - Don't expect to be done in a few hours (unless you have done this many times).
5 - Don't quit until you find best reading you want.
6 - If your receiver can handle only one sub, its best to keep them at equal distance. I agree that using phase knob, you can overcome this issue but I got the best results by keeping them at equal distance. Phase knob though did give me very good results with different distances but not as good as equi-distance.


After all the settings, I watched bass demo disk that LastButNotLeast has avialabe to download. It was amazing :-). Then I watched The dark Knight and thoroughly enjoyed it.

Finally I'll point out something that Criag brought to me attention (thanks again). To get real feeling when watching movie, why not install a device that works with LFE and shakes your seat to bring real feelings. It does a lot more than that. I mean it doen't just shake, it shakes differently based on the level of frequenecy. I'm getting mine on this Monday (can't wait :-).
http://www.crowsontech.com/go/crowsontech/3470/en-US/DesktopDefault.aspx

Enjoy.
post #417 of 757
Hi Sheraz,

It was great to meet you and your lovely wife last week. Thanks again for your hospitality.

I would like to point out a few things:

1. That above FR graph was acquired after a 3-position Audyssey run. We were just looking for preliminary results but they turned out to be so good that we kept them. I believe Sheraz ran an 8-position Audyssey run later, after I left. Maybe he can share his REW graphs as they would be better to compare against his preliminary REW graphs.

2. That above FR graph is only 1/6 octave resolution. Sheraz's graphs with REW will be higher resolution and will show more detail.

3. Unfortunately, I did not save any of the other graphs we ran that day. We probably took 30+ measurements while we re-positioned the speakers and subs. I only saved those last 2. Still, they're the most important.

4. The 2D waterfall graph may not be "self-explanatory." If anyone would like an explanation of what it depicts, I can explain it further. I did post earlier in this thread about them: http://www.avsforum.com/t/1490184/one-better-sub-or-two-subs/330#post_23812431
Quote:
My only concern (yeah they never end) is that rear speakers are way too far from the rest of speakers. They sound ok but I think I'm just going to increase them a bit in avr. Also surround speakers are at 8 feet hight and are pointing straight instead of pointing to MPL. I don't konw how much of a difference this will make. But, later on I'll change surround with Bi-polar surround speakers.
If you want to turn up the rear surround trims in the AVR, that's fine. Just write down the curent settings so you can go back to them if you want to later. I suggest you evaluate the changes with content that has signals in the rear channels, (i.e., 7.1 content), as opposed to using PLIIx or one of the other "matrixing" codecs turn create the rear channels. You'll want to ensure the rears don't over-balance the side surrounds.

Aiming the surrounds down at the ears should make them more directional. You'll need speaker mounts that allow them to be aimed. I use these: http://pinpointmounts.com/am40 Lowering them a little could help too. Bipoles would be good too.

Quote:
So sum the whole process up, I'd recommened to who ever is reading this post and trying to setup home theater to do the following

1 - don't sacrifice one part of your threater completely for another. If you are in plan mode, try to give sound and video equal attention. If either part is weak, your theater will be missing a lot.
2 - Don't only rely on your ears. Take measurements.
3 - Buy USB microphone and download REW (or use any other software that does the same). Don't waste time on using onlly Radioshack SPL. It is doable but very time consuming. Comparing cost of buying microphone vs effort of only using SPL to take reading, cost is much cheaper.
4 - Don't be afraid of using REW. Don't think its a big learning curve. It is not. If you have usb mice, its a piece of cake to get going. Use this guide http://www.avsforum.com/t/1449924/simplified-rew-setup-and-use-usb-mic-hdmi-connection-including-measurement-techniques-and-how-to-interpret-graphs/270#post_22823463. Use Frequence graph to check peaks and nulls and eliminate them by moving subs around. Read previuos posts to get ideas. There are many posts on that here :-)
4 - Don't expect to be done in a few hours (unless you have done this many times).
5 - Don't quit until you find best reading you want.
6 - If your receiver can handle only one sub, its best to keep them at equal distance. I agree that using phase knob, you can overcome this issue but I got the best results by keeping them at equal distance. Phase knob though did give me very good results with different distances but not as good as equi-distance.

Great stuff! ^^^ smile.gif

Craig
post #418 of 757
Quote:
Originally Posted by SherazNJ View Post

The purpose of this post is to summarize the whole process. I'll also post the final results we had. I had the pleasure to meet Josh Craig. He was kind enough to take some time (whole day in fact) from his busy schedule to pay me a visit. We had a few expresso and some cheesecake and then we started working on the theater.

Right away he pointed out how far I was sitting from screen. I was compromising screen size for sound. So we decided to find best spot for screen and then see if we can find it best for sound as well. So we moved around 13 feet away from screen. This definitely made screen look a lot bigger as compared to before. Doing so also made front and central speaker sound much better. Craig then noticed that for some reason, speakers didn't sound as sharp as they should. Playing around with avr settings, we found out that Home Theater EQ option was doing that. So we turned that off. Now the speakers sounded as we wanted them to.

Next was to figure out best spot for subs. It took craig on two tries to find the best spots :-). We moved one sub 5 feet to the frong from MLP in the hugging Left wall and other 5 feet to back from MPL hugging right wall. Basically both subs are at equal distances from MPL. We ddin't have to change phase at all to get good frequency readings. Here are two graphs that shows final results (after running Audyssey).





Everything sounded very well. Later after Craig left, I realized that my subs sounded better before. It was a mistake on my part becasue in previous positions, I was running subs hot. Anyway, I moved subs back to where they were and realized that reading wasn't as good and it didn't sound same until I turned gain know up and sub trim. That made me realized that craig did choose best spot in the first place. So I moved them back and turn gain know to 2 p.m.

Now everything sounds great. My only concern (yeah they never end) is that rear speakers are way too far from the rest of speakers. They sound ok but I think I'm just going to increase them a bit in avr. Also surround speakers are at 8 feet hight and are pointing straight instead of pointing to MPL. I don't konw how much of a difference this will make. But, later on I'll change surround with Bi-polar surround speakers.

So sum the whole process up, I'd recommened to who ever is reading this post and trying to setup home theater to do the following

1 - don't sacrifice one part of your threater completely for another. If you are in plan mode, try to give sound and video equal attention. If either part is weak, your theater will be missing a lot.
2 - Don't only rely on your ears. Take measurements.
3 - Buy USB microphone and download REW (or use any other software that does the same). Don't waste time on using onlly Radioshack SPL. It is doable but very time consuming. Comparing cost of buying microphone vs effort of only using SPL to take reading, cost is much cheaper.
4 - Don't be afraid of using REW. Don't think its a big learning curve. It is not. If you have usb mice, its a piece of cake to get going. Use this guide http://www.avsforum.com/t/1449924/simplified-rew-setup-and-use-usb-mic-hdmi-connection-including-measurement-techniques-and-how-to-interpret-graphs/270#post_22823463. Use Frequence graph to check peaks and nulls and eliminate them by moving subs around. Read previuos posts to get ideas. There are many posts on that here :-)
4 - Don't expect to be done in a few hours (unless you have done this many times).
5 - Don't quit until you find best reading you want.
6 - If your receiver can handle only one sub, its best to keep them at equal distance. I agree that using phase knob, you can overcome this issue but I got the best results by keeping them at equal distance. Phase knob though did give me very good results with different distances but not as good as equi-distance.


After all the settings, I watched bass demo disk that LastButNotLeast has avialabe to download. It was amazing :-). Then I watched The dark Knight and thoroughly enjoyed it.

Finally I'll point out something that Criag brought to me attention (thanks again). To get real feeling when watching movie, why not install a device that works with LFE and shakes your seat to bring real feelings. It does a lot more than that. I mean it doen't just shake, it shakes differently based on the level of frequenecy. I'm getting mine on this Monday (can't wait :-).
http://www.crowsontech.com/go/crowsontech/3470/en-US/DesktopDefault.aspx

Enjoy.

That's a great looking graph. I hope it sounds as good. Could you post some graphs with smoothing off? 1/6th octave smoothing masks a lot of details.
post #419 of 757
Quote:
Originally Posted by braveheart123 View Post

That's a great looking graph. I hope it sounds as good. Could you post some graphs with smoothing off? 1/6th octave smoothing masks a lot of details.

This! No more than 1/12 smoothing or none.
post #420 of 757
Quote:
Originally Posted by basshead81 View Post

No more than 1/12 smoothing or none.
1/6 is fine. You can't hear with better resolution than 1/6 octave, and with 1/12 you'll drive yourself nuts trying to get rid of every dip and bump.
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