Studio Acoustic Tiles/Panels for listening room?

Atzen811,
I use sonex tiles throughout my listening room (a 4ft tall strip that runs the circumference of the room, centered at tweeter level). I have a dedicated room however, and I can see why this would not be practical in a family room. I use it to iliminate slap echo in the high frequencies that can translate into image blur.

One problem with using too much of this material (i.e. 2", 3", 4" thick) is that it is not linear through the audio range. It attenuates less and less as you go down in frequency. Therefore, if you cover the whole room, you will have an unbalanced sound. Now, if you could have an ideal room with professional quality absorbers (very thick) that responded linearly down to a very low frequency, you wouldn't have to worry about this as much. Keep in mind that this is all theory, I've never experimented with this. But, as a general rule, the thicker the absorber material, the lower the frequency it can absorb.

Found even a little sonex or acoustic tile does something bad to the sound, maybe changes the phase, who knows...

Bufus is right. The attenuation is in the middle band and upper frequencies. It is likely to through the RT-60 (reverberation time for 60 dB attenuation) off. You typically need a variety of absorbers and diffusors to get the right balance in a room--I've never seen one material work.

Nonetheless, a little Sonex or RPG at the first order reflection points does wonders for signal to noise and coherence. I am now using the RPG "Studio in a Box" which inlcudes thick, wedge shaped pieces for the corners, large panels for absorption, and smaller tiles which cna be used in a grid pattern on the wall to create a diffusive effect. Combined with 3 RPG Skylines behind the listening position and with Corner Tunes, it works wonders on my otherwise far too reverberant room. Not someting, of course, you'd do in your living room unless you are single or looking for a good excuse to divorce.