when to splay/when to absorb and exposed ceiling joists

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telefunken
Posts: 29
Joined: Tue Sep 02, 2003 11:20 am

when to splay/when to absorb and exposed ceiling joists

Post by telefunken »

im going for exposed ceiling joists in my basement recording studio.
this is just from a acoustic point of view, not from a sound isolation point of view. between the joists, i had originally planned on having some soft fiberglass compress to 2" covered with sheetrock. and then a layer of 705 after that to deaden the ceiling and kill reflections from the floor. what if i was to have the outer layer between the joists left as sheetrock, but its angled at 12 degrees from right to left. would this eliminate the need for having the ceiling dead? the distance from the floor to the top of the sheetrock between the joists would be roughly 9 ft.
telefunken
Posts: 29
Joined: Tue Sep 02, 2003 11:20 am

Re: when to splay/when to absorb and exposed ceiling joists

Post by telefunken »

anybody?
dymaxian
Senior Member
Posts: 357
Joined: Tue Dec 02, 2003 7:21 am
Location: Madison, Wisconsin

Post by dymaxian »

If you want an absorbent ceiling, just eliminate the gyp board, I'd say. With whats left in your description, you should be fine.

Batt insulation between the joists and 703 across their bottoms? Is that what you meant? If so, then every joist space becomes a bass trap.


Kase
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Kase
www.minemusic.net

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telefunken
Posts: 29
Joined: Tue Sep 02, 2003 11:20 am

Post by telefunken »

no im asking if you can have a live 9 ft ceiling, by angling the sheetrock between the joists at 12 degrees so its no longer parallel with the floor.

anyone?
knightfly
Senior Member
Posts: 6976
Joined: Sun Mar 16, 2003 11:11 am
Location: West Coast, USA

Post by knightfly »

If you mean like the ceiling was a "sawtooth" shape, it will help reduce flutter echo some, but modally the ceiling wil act mostly as if it were the average between low and high distance to floor. Realistically, you'd only vary the height by roughly 4-5 inches, so all that would do modally is flatten the response peaks caused by your ceiling height slightly.

If you're listening to speakers in that room, you would also get some early reflections off the ceiling from the vertical side of the "teeth", which could very easily end up right back at your ears, and 'way too soon for clear imaging. That's why low overhead beams are normally boxed in and absorbed... Steve
telefunken
Posts: 29
Joined: Tue Sep 02, 2003 11:20 am

Post by telefunken »

knightfly,

the angling of the sheetrock between the joists would be in a live room. the room dimensions are 35x15 w/ 9ft ceilings [at their highest point since the joists are exposed]

i know the modes arent the greatest but i plan on building a lot of the ethan weiner style panel bass traps, roughly 14 spread out throughout my live room.

would angling the sheetrock between the joists work in this application or no?
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