John Sayers' Recording Studio Design Forum Archive

The room is 15' wide by 12.5' deep.
There is a double wall with double windows (1/4" laminated on each side 5" air gap) between the control / live room.

The speakers are Mackie HR824 soffited into the front corners of the room.
There is spare space underneath them (bass trap?).

The rear of the room has 2 deep bass traps (2' X 6') side by side and there are two small cavities on both rear corners covered with a cloth filled with roxul 3" fiberglass.

Finally, the ceiling also has an 15' angle starting at the the front of the room (~ 7'-8") window and going to to the middle of the room and then there is a full 95" of height on the back.

Where would you put absorbers and where would be the best place for bass traps in this room ?

Thanks
Dan

Dan,

> Where would you put absorbers and where would be the best place for bass traps in this room ? <

The short answer is bass traps go in the corners, and that includes the corners where the walls meet the ceiling (and optionally the floor). Mid/high frequency absorbers go on the walls and ceiling, and in particular the first reflection points.

For the complete story, see the Acoustics FAQ, second in the list on my Articles page:

www.ethanwiner.com/articles.html

--Ethan

Ethan,

Thanks for the quick answer - that is what i wanted to be sure of before making the bass traps.

I do have some large pieces of 703 (one inch and a half thick) that can go all the way up (ceiling) and down (floor) in the two rear corners of the CR.

All covered with a tissue (cloth).

How much air gap would you recommend ...?

Right now, i can go with a good 4 to 6 inches at each corner.

Regards,
Dan

Dan, 4-6 inches, other than in panel (or possibly slat absorbers) doesn't constitute a bass trap - for a broadband absorber to get into the bass region requires a few FEET of distance between the face of the absorbent and the boundary (wall) - this is why a good start is 4 foot wide (and preferably 3-4" thick) rigid fiberglass or rockwool diagonally across corners of rooms.

If you don't have that kind of space, consider Ethan's panel trap designs for DIY; they work on different principles, and will only take up 5-6 inches out from your walls... Steve

Dan,

> How much air gap would you recommend ...? <

As Steve said, if you mount them straddling the corners the air gap that forms naturally behind the panels will be fine.

--Ethan