Regarding Post 73:
You might try removing the diffusers on the ceiling and try something else. In many cases, the reflection off of the ceiling above and in front of the speakers may be a major culprit. Assuming your speakers emulate a point source, reflections off of the walls will be that of a point source - delayed in time, and with the characteristics of the wall included. However, reflections off the ceiling are always fairly garbled, since the arrival times at that point from the various drivers will always be staggered in time. Lower ceilings are more problematic, since more of what you are hearing is this time delay.
Two ways that you might approach this - both above and in front of the speakers on the ceiling; 1) Pressed wool felt, 1/4" or thicker - F-13 density (available from Sutherland Felt (on line - item 713-4, about $40 per 72" lineal yard); if it is a really significant problem: 2) Build an open frame, or several frames about 1" thick. Stretch an attractive fabric over them, and fill it with strips of carded top wool (Brown Sheep Wool - Scottsbluff, NE - $20 per pound, white or various colors). This is a "black hole" for absorbing frequencies in a linear fashion down to below midrange frequencies. These methods are also good for dealing with side reflections. If you want more details about constructing these, you can contact me at
mosaicaudio@yahoo.com.
If you are using any fiberglass absorbers or diffusers, take them out and try the above.
Regards,
Dale Pitcher