NYOB asked:



How many subwoofers are you using?
Are you speaking of multiple drivers or
of actual subs in cabinets?


On the left side of the room I have a Definitive Technology 15" sub and
a Velodyne 12" sub (fed from the left channel. On the right side I have
two old AR3s (mid and high disconnected) plus a damaged Velodyne (woofer
is OK but the amp is toast) fed from the right channel through an Apt 1
amplifier. The room is 22' X 30' with an 18 foot cathedral ceiling.
All the subs are fed through networks that limit the bass to frequencies
below 100 hZ. My main speakers are DBX Soundfield Ones that have the
bass slider on the control unit set at minimum. The room tends to be
boomy in the low mid bass and corner placement of the subs makes this
worse so the subs are placed about mid way along the side walls.

---MIKE---


According to Tom Nousaine's research having subs on opposite sides of
the room is a bad idea, and in all cases they should be in a corner.
Not doing so reduces the gain from having 2 drivers from the normal 6
dB to 4.5 dB.

Then there's the problem of notching caused by subs in different
locations, even if they are both in corners.

If at all possible you should move all subs into the same corner. I
don't recall anything about the AR3 other than I don't think it was
ever intended to be a subwoofer and I doubt it can provide anything
below the 30's in terms of low end response. Also, the 100 HZ xover is
I'm sure you've been advised to high to prevent any of them from being
localized. Tom's research confirms the THX standard of 80 HZ as the
highest point possible to keep the subs from being detected as separate
sources.

Of course at low frequency xover oints mono is better than trying to
get 'stereo' bass, particularly since there is no stereo at 80 Hz or
lower.

You should see if you can get your hands on the article from Stereo
Review January 1995 and read Tom's article "Subwoofer Secrets." His
investigation into best placement of subwoofers is very thurough and
definitive.

If you can't get a hold of it e-mail me and I can send a copy.
It may be available in the archives of Sound&Vision's web site.