Dick,

I DARE you to quote me making the statement

Yes, that was paraphrased from memory. Fortunately Google Groups saves all
this stuff. Here's exactly what you said: "False, what you are claiming is a
physical impossibility. If you have a dip at 75 Hz, the CLOSEST a peak could
be is 1/4 wavelength away. You have to go through 90 degrees of phase
rotation for this to occur."

And now I can see why there's some confusion. The concept of "peak" and
"null" is confusing in small rooms because there are so many reflections
bouncing off so many nearby boundaries. So suppose you locate a deep null
and then move away in one direction. If the level comes up and goes down
again, that doesn't mean the highest point is actually a peak that's related
to the same nearby null.

If you recall, I measured a null in my room and found a 15 dB change across
a span of only four inches. And that's what really matters - the fact that
this happens, not how or why. Back then we were talking about the futility
of trying to fix room acoustics with DSP. Now Carlos has embarked on an
equally futile mission of trying to solve his room acoustics problems with
speaker placement.

This past Saturday my partner and I did some tests of speaker placement, to
see how much the response could be improved by mere placement. We went to
the considerable effort to remove all of his acoustic treatment and even the
carpet, to maximize the room contribution. Sure enough, and no surprise to
anyone here, some speaker locations had a flatter low frequency response
than others. But the peaks and dips were very severe in all cases. Then we
put the speakers against the wall again (not the flattest response) and put
back his bass traps and mid/high absorbers. The improvement was FAR better
than the best speaker location we had found.

We still have some tests to do using our newer, better bass traps. When
that's done we'll post on our company site graphs comparing the flattest
response you can get with placement versus what you get with proper acoustic
treatment. Carlos, if you're interested let me know and I'll post a screen
capture of what we have so far with our older model bass traps. It clearly
shows that treatment beats placement hands down every time.

--Ethan