Subwoofer gain based on corner location/proximity, how to do the arithmetic?

[Paul McNeil]

I have two subs (SVS cylinders) in one corner, and three stacked (Klipsch THX 120) in another.

The SVS are set to a gain of -32dB (to accommodate Auydyssey/Dirac correction via a Marantz AV10). So these guys are set way low. The Klipsch are powered by Crown amps, so no numbers there.

The question is, how much gain do I get from two SVS, next to each other in one corner? And how much from three stacked Klipsch, in the other?

I've seen, if my memory serves, +6dB from closely placed subs, and +3dB, from the corner placements.

How to do the arithmetic? Is it simple addition? How much gain from the two SVS in one corner, and three Klipsch in the other?

PS I have REW and could measure for an answer, but am too lazy...

 

[ski2xblack]

You've go a couple things affecting this, 1) Colocated subs will increase output 3db (maybe 6db? can't specifically recall). And 2) corner loading increases output significantly more (think in terms of full space, half space is +6db, quarter space anoter +6db, eighth space another +6db).

Of course that's kind of crude, but you get the idea.

 

[TLS Guy]

I have two subs (SVS cylinders) in one corner, and three stacked (Klipsch THX 120) in another.

The SVS are set to a gain of -32dB (to accommodate Auydyssey/Dirac correction via a Marantz AV10). So these guys are set way low. The Klipsch are powered by Crown amps, so no numbers there.

The question is, how much gain do I get from two SVS, next to each other in one corner? And how much from three stacked Klipsch, in the other?

I've seen, if my memory serves, +6dB from closely placed subs, and +3dB, from the corner placements.

How to do the arithmetic? Is it simple addition? How much gain from the two SVS in one corner, and three Klipsch in the other?

PS I have REW and could measure for an answer, but am too lazy...

Not simple, but actually impossible.

You will have to use REW. But even after that low bass levels need to be st by ear, as these measuring mics are not that accurate in the low bass.
So in the region around 20 Hz you have to take the results of these measuring devices, with spoonfuls of salt.

I can't imagine why you need all that sub power. And another thing, using different subs is not a good idea and creates problems on its own account.

 

[Paul McNeil]

Not simple, but actually impossible.

You will have to use REW. But even after that low bass levels need to be st by ear, as these measuring mics are not that accurate in the low bass.
So in the region around 20 Hz you have to take the results of these measuring devices, with spoonfuls of salt.

I can't imagine why you need all that sub power. And another thing, using different subs is not a good idea and creates problems on its own account.

Why all that power, well, cone extension and therefore distortion minimized. Different subs a problem?! Some say better. Where is the data, blind testing or REW?

 

[Paul McNeil]

You've go a couple things affecting this, 1) Colocated subs will increase output 3db. And 2) corner loading increases output significantly more (think in terms of full space, half space is +6db, quarter space anoter +6db, eighth space another +6db).

Yep, those two variables!

 

[TLS Guy]

Why all that power, well, cone extension and therefore distortion minimized. Different subs a problem?! Some say better. Where is the data, blind testing or REW?

You absolutely don't need that many subs to achieve acceptable distortion.

Using different subs means you have sources with different FRs, which means achieving a good in room response is next to impossible.
They won't phase well, which will cause frequency cancellations and a real mess. It is a bad plan.

 

[ski2xblack]

Not that it's what you asked about, but I concur w/ TLS. Two identical Hsus would be preferable to mixing in the Klipsch subs.

Corner loading is a mixed bag. The extra boundary gain can help sealed subs achieve deeper extension in room, without herculean amps or eq. But it can really excite modes, too. At least that's been the case in my office rig that has a couple sealed subs stuffed into the corners.

 

[Paul McNeil]

You absolutely don't need that many subs to achieve acceptable distortion.

Using different subs means you have sources with different FRs, which means achieving a good in room response is next to impossible.
They won't phase well, which will cause frequency cancellations and a real mess. It is a bad plan.

I use Dirac Live Bass, to take care of the problems you mentioned, and my in room response, as measured by REW, is superb.

 

[Paul McNeil]

Not that it's what you asked about, but I concur w/ TLS. Two identical Hsus would be preferable to mixing in the Klipsch subs.

Corner loading is a mixed bag. The extra boundary gain can help sealed subs achieve deeper extension in room, without herculean amps or eq. But it can really excite modes, too. At least that's been the case in my office rig that has a couple sealed subs stuffed into the corners.

Yep, not what I asked about, at all...

 

[TLS Guy]

Yep, not what I asked about, at all...

You asked a question that has no answer, but we did take note that your system design is highly irregular and frankly in the Frankenstein category.

 

[Paul McNeil]

You asked a question that has no answer, but we did take note that your system design is highly irregular and frankly in the Frankenstein category.

Noted! I guess I'll just lie low for a while...

 

[jinjuku]

The +3 and +6 #'s are going to be correct. It's just that others here are saying the integration may be difficult.

If you decided to run some of the sub's that don't have the bottom end like the others as mid-bass modules that may make for an improvement.

You haven't received bad advice but I don't see you open to constructive input either. You'll get out of this site and it's members what you are willing to get out of it.

 

[William Lemmerhirt]

I use Dirac Live Bass, to take care of the problems you mentioned, and my in room response, as measured by REW, is superb.

I remembered your other thread about calibrating your subs with audyssey. They had a trend that was sloping downward from 70 to about 20.

Did Dirac do better than this?

 

[Paul McNeil]

I remembered your other thread about calibrating your subs with audyssey. They had a trend that was sloping downward from 70 to about 20.

Did Dirac do better than this?

Yes, William, Dirac did! Thanks for the interest. Here's the REW response (no smoothing) for all subs operating together and separately for the SVS and Klipsch. You may remember that you were concerned, rightly, about the sub 20 htz bass, which the SVS should have been producing but did not with Audyssey. Well, it's now there with Dirac.

 

[Paul McNeil]

You haven't received bad advice but I don't see you open to constructive input either. You'll get out of this site and it's members what you are willing to get out of it.

I didn't ask for advice or evaluation of my system and said so after the second such post. I did not get constructive input, indeed, my system was labeled a Frankenstein monster, ugly, unpredictable and violent! Oh my.

Please see my REW measurements above (reply to William), for an objective evaluation that takes into account room size/shape, seating position and bass management, none of which my previous evaluators asked about.

 

[Paul McNeil]

You asked a question that has no answer, but we did take note that your system design is highly irregular and frankly in the Frankenstein category.

Please let me know what you think of the REW measurements posted above.

 

[PENG]

Yes, William, Dirac did! Thanks for the interest. Here's the REW response (no smoothing) for all subs operating together and separately for the SVS and Klipsch. You may remember that you were concerned, rightly, about the sub 20 htz bass, which the SVS should have been producing but did not with Audyssey. Well, it's now there with Dirac.View attachment 67988

I don't remember if I mentioned this in your other thread, but I'll do it again even if I did just in case.
Obviously Audyssey did not do it for you, but for clarity, I would say that Audyssey, without manual adjustments to the target curve, did not do it (that is, level the deep bass for you).

The clarification is, at one point, Audyssey limit the deep bass somehow such that it would not be flat to 20 Hz. I forgot the reason, other than it was meant to "protect" subs, speakers, that are not design to extend that low.

I think if I search hard I may be able to find the target curves for the subwoofers that shows the intentionally deep bass tilt down and the flat one. When MultEQ Editor app first came out, it was flat, and I don't remember when, probably around 2012, it became tilted down, and then D+M made it flat again later.

I did manage to find my own screen shots that compare the tilted and flat subwoofer target curves below:

Before I updated the MUltEQ editor app:

You can see clearly that the updated app resulted in the kind of bass tilt you seem to be getting.

I am not sure if you happened to be using the App version that was before D+M updated the target curve back to flat and would therefore have a downward tilt based on the measured response.

If you do have the updated version, then I don't know why you were still losing a few dB from below 70 Hz vs Direct Live, except perhaps you left the intended bass upward tilt that Dirac Live would apply by default since around 2 years ago. Earlier on their default curve was almost flat, not much different than Audyssey's.

I know this can be confusing for you, but since you prefer data, and I happen to have the data that shows Audyssey (it could be just D+M as they took over it from Audyssey when they launch the app) did put a downward tilt at one point depending on the measured response of the subs, but later restored it to flat, whereas DL went the opposite way, and introduced the upward tilt, probably because by then they knew people were talking about the "Harman curve". Note: Haman did not call or invent that kind of curve, but they published their findings, in stud(ies), that showed most people prefer an upward tilt from around 200 Hz to 20 Hz.

Also, note that while Dirac Live's default target curve would have an upward tilt, the slope would differ between different calibration runs, as it obviously tried to vary the magnitude, based on the measured results, so it may add a couple of dB at the end point (20Hz), but could be as high as 5 dB or more.

After updated the app:

 

[TLS Guy]

Please let me know what you think of the REW measurements posted above.

I think that the klipsch are not bringing much to the table. It looks as if the SVS subs would be adequate.

 

[Paul McNeil]

I think that the klipsch are not bringing much to the table. It looks as if the SVS subs would be adequate.

As I said before, I like minimal cone excursion, because that minimizes distortion. So, yes the Klipsch are, bringing something to the table.

But I have to ask, TLS, is this the Frankenstein bass response you expected, from my monster? I'd love to see your measured REW response, I do appreciate data, especially deep in the bass region (where most, without bass mangement (such as Dirac), are listening to their room, not their expensive subwoofer!

 

[Paul McNeil]

I don't remember if I mentioned this in your other thread, but I'll do it again even if I did just in case.
Obviously Audyssey did not do it for you, but for clarity, I would say that Audyssey, without manual adjustments to the target curve, did not do it (that is, level the deep bass for you).

The clarification is, at one point, Audyssey limit the deep bass somehow such that it would not be flat to 20 Hz. I forgot the reason, other than it was meant to "protect" subs, speakers, that are not design to extend that low.

I think if I search hard I may be able to find the target curves for the subwoofers that shows the intentionally deep bass tilt down and the flat one. When MultEQ Editor app first came out, it was flat, and I don't remember when, probably around 2012, it became tilted down, and then D+M made it flat again later.

I did manage to find my own screen shots that compare the tilted and flat subwoofer target curves below:

Before I updated the MUltEQ editor app:

You can see clearly that the updated app resulted in the kind of bass tilt you seem to be getting.

I am not sure if you happened to be using the App version that was before D+M updated the target curve back to flat and would therefore have a downward tilt based on the measured response.

If you do have the updated version, then I don't know why you were still losing a few dB from below 70 Hz vs Direct Live, except perhaps you left the intended bass upward tilt that Dirac Live would apply by default since around 2 years ago. Earlier on their default curve was almost flat, not much different than Audyssey's.

I know this can be confusing for you, but since you prefer data, and I happen to have the data that shows Audyssey (it could be just D+M as they took over it from Audyssey when they launch the app) did put a downward tilt at one point depending on the measured response of the subs, but later restored it to flat, whereas DL went the opposite way, and introduced the upward tilt, probably because by then they knew people were talking about the "Harman curve". Note: Haman did not call or invent that kind of curve, but they published their findings, in stud(ies), that showed most people prefer an upward tilt from around 200 Hz to 20 Hz.

Also, note that while Dirac Live's default target curve would have an upward tilt, the slope would differ between different calibration runs, as it obviously tried to vary the magnitude, based on the measured results, so it may add a couple of dB at the end point (20Hz), but could be as high as 5 dB or more.

View attachment 67989

After updated the app:

View attachment 67990

I think I was using the updated version of the phone app (is this what you mean by
D+M. But in fact the processor alone gave a better, but still inadequate low end bass response. I did manually correct the Audyssey bass, of course. I had to! But I lost faith in Audyssey, as I previously posted, and spent +$800 dollars for Dirac including Bass Control. I had to, otherwise I had a $7k AV that, out of the box, sucked in the bass region. And, by the way, the high end is also better with Dirac, no 'curtain' necessary at the S frequency.