Pg 14 - Center Speaker Masking
My entire design for the center channel speaker behind the screen is based on recommendations from THX. The screen itself is THX certified, as are the micro-perforations. THX specs minimum distance from speaker to screen and the Johns Manville Linacoustic fiberglass you see lining the cavity behind the false wall. To reduce/eliminate sound reflections between the speaker and the screen which causes cancellation of certain frequencies, i.e. comb filtering, they recommend that the speaker face be covered with the same 2" fiberglass.
After several, um . . "prototypes" I was able to get the cutouts lined up with the drivers. The holes were cut with a standard razor blade knife. So that the 2" thick fiberglass would not constrict the dispersion pattern I have tapered the sides of the cutouts with a cheap electric razor. I emphasize “cheap” because after shaving ‘glass, it pulls whiskers rather than shaving them.
Here is the completed and attached fiberglass mask.
Here is what it looked like before I added the fiberglass . . .
. . . and here it is completed. Also, as per THX, I have covered the 1x4 framing where the screen mounts. These fiberglass modifications have allowed me to EQ the center speaker to a much closer timbre match to the L&R speakers.
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