Originally Posted by BIGmouthinDC
Localhost127: having read a number of your posts your advice is running contrary to a couple of Theater designers/audio advisers who have hung out here over the years, specifically Dennie Erskine and Brian Pape I would to see you guys have a discussion on treating a dedicated theater space
Maybe, but only to the degree that others are mistaken or that one may have misinterpreted them.
Faced porous material is used ONLY to minimize the mid and HF absorption of LF bass trapping!
It is absurd to use faced material as absorption for early arriving high gain reflections as it is reflective to frequencies above ~600 Hz!
This material is well known in studio design and has been for years!
The biggest problem being that too many people are using too thin material that fails to be effective over the entire broadband specular bandpass, effectively EQ in the reflected energy causing coloration when it superposes (sums) with the direct signal!
This behavior of the material faced with at a minimum of at least 6mil plastic is precisely what is leveraged in the large LF corner 'superchunk' style bass traps in order to create frequency selective bass traps in order to retain the finite amount of mid-high energy in the room. (Also, for such large volume traps, the 'pink fluffy stuff' offers superior performance compared to the more traditional OC703 or 705 (3pcf or 6pcf respectively) material.
And using what is expedient rather than what is correct is NOT the proper/effective way to treat a room!
Originally Posted by adidino
Why not OC 705 2 or 4 inch? I'm using it in my dedicated my room and reflections are pretty well controlled. Some eq'ing was needed but nothing dramatic.
No. The problem with this is that while it does fine on the upper mids and highs, it is not sufficiently effective on the higher energy content lower-midrange specular energy. Absorption for specular reflections to be effective must be broadband. That means that it must absorb effectively over the full bandpass from ~300 Hz up. The highs are easy, the mid range is not.
The problem is that such treatment only modifies the spectral content of the reflected specular energy. It does not effectively absorb the energy and unfortunately the problems caused by the superposition of such energy not only is not remediated, but the resulting spectral imbalance that causes the indirect energy to now be significantly different from the direct energy causes additional coloration. In other words, you either do it properly and completely, or you cause more problems.
And you do NOT
use EQ to remediate non-minimum phase spectral issues!!!!!!!!!!!!