Originally Posted by jim19611961
Firstly, I would try and run your speakers without the grills. They themselves create early unwanted reflections. As far as engulfing the speaker in PF, it just depends on what early reflections you have and their source. Ditto for the wall behind your speakers.
When I originally made the new grills for my three Genelc 1038's I saw a large number of reflections within the first 3mS. When I removed the grills they went.
What I discovered was that the 1/2" MDF that I was using for the frames were causing edge refraction above 8KHz. I fixed it by:
1. making the main speaker grill surround only 3/4" wide and removing all cross braces
2. Rounding or chamfering all inside edges
3. Chamfering all outside edges where they "bled off" into absorption areas.
This seemed to remove the bulk of the early refections from the grills. I applied this process to all my grills for the heights and rear 1038's for music.
In my case the LHS & RHS of the L/C/R speakers "bleed off" into surrounding absorbers, this ensures minimal edge refraction. See my room cross sections above or my link for more detail.
It is important that if your speakers are flush mounted that any gaps between them and their surrounds are very small and ideally filled with absorber. On top of that the speakers need to be resiliently mounted and acoustically isolated from their surroundings to stop early early sound but rigid enough so as not to move with heavy bass transients.
Any walls behind speakers should be heavily treated with absorption and preferably filled leaving minimal air gaps unless some air circulation is required, as in my case, to cool the speakers electronics. Remember if the front sound wave can reach the rear of the speaker and be reflected from it significant cancellation will occur as a function of that spacing. Please see my earlier comment.Edited by Digione - 11/13/13 at 5:30pm