Originally Posted by Axiom Maniac
Is finding the first reflection point something to do with moving a mirror on the wall behind the sweet spot until you see the speaker in the front? I remember this only vaguely from a text long ago.
Have a helper slide the mirror along the walls and ceiling....If you see the speaker baffle (grill) in the mirror (when sitting in your seat) then that speakers sound is bouncing off the wall and hitting your ears... only it traveled further than the same sound you heard directly from the speaker... so it took longer to get there.... because the distance is only slightly longer the spl (volume) is almost as loud as the direct sound.
Take for instance your center.... if you can see it at one place on the ceiling, 1 on the left and right side walls and one on the back wall (the floor if it's not carpet).... that's four or (five with hard floors) places that sound is bouncing off and and hitting your ears along with the direct sound... now do this for every speaker in the room.... it's like several people standing around you all talking at once....talk about a muddy mess.
Treating the front wall is kinda optional... the only reflections you'll get are from the surrounds which are diffused for most of use anyway and because of the very long distance the spl will be very low.. I tryed it and found that it didn't need to be done. If you have rear ported speakers close to the wall a panel behind them can help quiet port noise and resonance.. but again very minimal improvement and I think most that treat the front wall only did it because someone told them they needed to...But as far as the mains and center go the front wall is in no way a first refleciton point.
No speaker can perform any where near it's best in an untreated room... the difference is jaw dropping.
DIY panels can be built for around $18 per. I did my movie room for around $200.
This is what I used and about the best price you'll find.http://www.atsacoustics.com/item--Ro...f-6--1006.html