And so it came to pass, on 06-30-97 07:10,
   that DAVID SCHMOLL spake unto MATT ION:
 MI>> Bingo!  Driver efficiency VERY MUCH comes into play.  If the amp
 MI>> driving a
 DS> That is why this section of the book jumped out at me and prompted
 DS> me to ask for a second opinion, since I had never heard this
 DS> particular theory before.
Me neither.  Sounds rather bizarre.  In fact, it sounds like something 
written by someone with a little theoretical knowledge and no practical 
experience.
 DS> For example: the room has brick on the side walls and behind the
 DS> choir and the room echo's like crazy. 
Ouch!
 DS> The room supposedly has a resonance at 250 hz, so the 1/3 band EQ
 DS> has all bands below 50 hz cut, 
And this is supposed to help to 250Hz resonance how?
 DS> the 250 and 500 bands cut, 
UGH!  500 too?  I don't expect subharmonics of 500Hz would be THAT much of a 
problem...
Frankly, I believe the brick would cause more mid-high reflection than 
anything.  250Hz is more in the range of room standing waves, I would think.
 DS> as well as several other higher bands cut (all -15 db), creating
 DS> holes that I feel destroys the balance to my ears. 
NO KIDDING!  That kind of EQ curve will hurt ANYONE'S ears!  It's almost like 
an intentional comb filter.
 DS> I suggested treating the brick walls before exploring a different
 DS> speaker system, since that problem will remain - the sound man
 DS> agreed, but church politics comes into play.
What kind of "politics"?  Yeesh, treatment could be as simple as some nice 
black panels - wooden frames (1x2 or 1x4 would suffice) covered with an 
opaque black cloth would deaden the upper end nicely.  Put some acoustic 
wedge foam behind the cloth to help break up the standing waves.
 DS> Another option was to get the Berringer DSP8000 EQ, so the band
 DS> cuts could be cut in smaller slices than 1/3 octave, but the people
 DS> that installed this system, are against that, as it would change
 DS> the system too much, and they won't stand behind it then.
I agree, that's a little extreme... and it's only treating the symptom, not 
the problem itself.
 DS> All I know is I hear bass and echo problems, and I'm attemepting to
 DS> find out more about the system, so I can offer suggestions if
 DS> anybody is receptive to them. I'm actually a bass player, but the
 DS> bass mix in the room is not very good, so I have put off asking to
 DS> play for now. In the meantime the soundman is teaching me the sytem.
First thing I would do is get ahold of a good RTA (or even a cheap one, in 
this extreme instance) and run a frequency sweep on the room.  Set the EQ 
flat, pump some pink noise through the system, and the RTA will give you a 
good idea of where to tweak the EQ.  Adjusting speaker positioning and 
placement - for example, making sure the speakers are not aiming directly at 
a flat wall at right angles to that wall - would help as well.
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Love, luck, and lollipops...
Matt


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