RevMen
The Reverend Menacer
It really isn't important. All (typical) absorbers absorb in the high frequencies, with lower frequencies being absorbed as thickness increases. So as long as you have enough thickness to catch all the directional frequencies (down to 500 to 1000 Hz) you're good to go. The point of the first reflection absorbers isn't to achieve spectral balance. It's to clarify directionality by removing signals that may confuse your ears about the origin of the source.That's very true. What I am wondering is how do you examine the spectral content of the reflection? Without that information aren't we guessing at for instance, how deep or thick our absorber needs to be?