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You've got "experts" -- I've got "experts" But none of them agree on sub locations (the right answer is "I don't know!")

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Richard BassNut Greene

In Reply to: "Quotes can be BS too" is not an argument posted by Duke on March 12, 2007 at 11:03:20:

This is a two-channel audio forum.
Subwoofer recommendation for home theater may not apply to a single two-channel audio sweet spot.
Subwoofer recommendations vary among experts and among manufacturers such as REL and HSU.
The Welti research makes assumptions that rarely apply to two-channel audio (equalization) and he admits in writing there is no way of knowing if his measurements correlate with subjective impressions of real audiophiles!
So the obvious answer to whether adding a third or fourth "scattered" subwoofer will benefit the sweet spot seat in a two-channel audio room is "I don't know".
That has been my answer all along.
From a transcript of: "Multiple Subwoofers for Home Theater" originally presented by Tom Nousaine at the 103rd Convention of the Audio Engineering Society, September 1997 (preprint 4558)
" ... in the subwoofer range, a single one (subwoofer) in the corner beats the pants off five-in-the-round ... So in summary, at least this experiment showed that one sub in the corner beats any combination placed elsewhere. ... If you have two or three subwoofers and you want the best performance, stack them all up in the same corner ... So the best thing you can do is to put your subwoofer in the corner and excite as many of the modes as you can as hard as you can!! What that does is give you the smoothest possible response in that room, although it may not be perfect."
So which expert is right?
You seem to know.

I don't.
.
.
.
.

Richard BassNut Greene
Subjective Audiophile 2007

Follow Ups:

My turn to question - Duke 14:02:08 03/13/07 (3)
Hi Richard,
Thank you very much for the Tom Nousaine reference.
I printed out a copy of AES Preprint number 4558 and could not find that quote you gave anywhere in the paper.
However, Nousaine does clearly state that one subwoofer in a corner measured smoother than five placed where his left, right, center, and two surround speaker normally go in his home theater system.
Nousaine is showing in-room measurements of plus or minus 3 dB from corner placement of a subwoofer. Richard, that simply does not sound right to me! Does that sound right to you? Is it really that simple - just put the subwoofer in the corner??
I once tried designing a speaker specifically for corner placement, and I am absolutely convinced that any speaker measuring plus or minus 3 dB from 100 Hz on down when placed in a corner had to be designed (or equalized) specifically for corner placement. Imagine moving a Klipschorn out into the room like a normal speaker. What would happen to the bass response?
The only way I can see Nousaine's subwoofers measuring so smooth in a corner is if they were designed specifically for corner placement. If that is the case, then no wonder they measured poorly when placed elsewhere (weak lower bass, as would be expected).
Also, you earlier made a strong case for scattering subs in the vertical plane (if multiple subs are used) to smooth out the floor-to-ceiling mode. Did you notice that the shape of the frequency response curve did not change when Nousaine stacked five subs in a corner? Only the amplitude changed. That is very, very strange - the implication would be that changing the height of a low frequency source has absolutely no effect on the floor-to-ceiling mode. With apologies to the bald-headed bad guy in The Princess Bride - inconceivable!
I did a search to see how widely Nousaine's paper is being cited as a source. Since its publication in 1997, one paper mistakenly attributes a statement on "envelopment" to Nousaine's paper, and another cites him as a "supplemental source". No papers are citing Nousaine's amazing "discovery" that corner placement results in the smoothest possible in-room response. Zero. If Nousaine was considered a credible source on the subject of subwoofer placement by the academic community, you'd think someone would have used his monumental findings in the ten years since his paper was published.
In contrast, Welti's "How Many Subwoofers Are Enough" has been cited in 17 papers since it was published in 2002.
So... my expert's friends can beat up your expert's friends!
Duke
- I think I have just enough steam left to get in the last word - Richard BassNut Greene 15:10:18 03/13/07 (2)
  The Nousaine quotes were all taken from an 11-page Nousaine article in the February 1988 issue of the Prairie State Audio Construction Society newsletter SOUND BYTES. The article was said to be a transcript of Nousaine's presentation to the audio club a few weeks after his AES presentation on the same subject.
  I can't find my 4558 preprint to quote from it.
  If I wanted the loudest bass possible in my room, then one or more subwoofers in a corner with parametric EQ to eliminate all bass peaks at my sweet spot would be the answer. But my main speakers are 8 feet from the front wall and five feet from the side wall, so using a one corner subwoofer makes it sound like a bass player is standing alone in the front corner of my room!
  Subs "stacked" in a corner may really be side by side in a corner rather than all stacked vertically to the ceiling.
  All the measurements we have don't mean much if they are not confirmed by real audiophiles experimenting with subwoofer locations/quantities in their own rooms.
  The ONLY conclusions I have from 25 years of experimenting iare:
  (1) parametric equalizers are great "band aids" for subwoofers,
  (2) a dozen bass traps are good if the wife will allow them (two don't make much difference), and
  (3) side and rear subwoofers are much less likely to be sonically invisible than front subwoofers located near or between the two front speakers of a two-channel audio system.
  I can't even say for certain that adding a second subwoofer will benefit the two-channel sweet spot seat in a particular listening room, much less a third or fourth!
  I'm sure "experts" who claimed the world was flat were cited many times ... before people found out they were completely wrong!
  My current tube subwoofer places a 15" driver behind my left speaker, four feet off the floor, firing up at a slanted ceiling that is about nine feet tall above the driver. This location requires three bands of parametric EQ. If I reverse the subwoofer 180 degrees so it is downfiring at my cement slab floor, the frequency response becomes so bad that after an hour of trying to equalize it, I just gave up.
  This worst sub driver position I'd found since 1987 ... was a mere 4 feet away from the best sub driver position I had found.
  Who could have predicted that?
  Okay it's long past time for us to reverse positions and start a new argument. My new theory is that if your home has a street address that is an even number, then you should use an even number of subwoofers. I could cite many studies for this hypothesis ...
  if there were any.
  
  Richard BassNut Greene
  Subjective Audiophile 2007
  - Show's over folks. Move along. - Duke 15:23:28 03/13/07 (1)
    Well Richard, my horse has long since been beat to death, and yours ain't lookin' too healthy neither.
    Seriously, I learned a lot from this. Thank you.
    Duke
    - They were all snoring after my third post ! - Richard BassNut Greene 08:49:18 03/14/07 (0)
      Except Welti who took his toys and went home mad.
      ,
      ,
      ,
      
      Richard BassNut Greene
      Subjective Audiophile 2007

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