#1647399 - 04/02/04 12:08 PM
Phil Cramer's Bass Trap Design Questions
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SlimJim
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Registered: 03/26/04
Posts: 6
Loc: Washington, DC
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Hey Ethan,
I took your advice and came to this forum. Great form! Great insight!
A few questions about the bass trap design by Phil Cramer on your site.
1)Can you back these with MDF board panels to make them more mobile? 2) Are the mid/high traps mid/high bass or mid/high freq, 1K-20K (I'd assume mid/high bass)? 3)What are the freq ranges per trap?
4)And how many for a room 20'd x 14'w x 7'h? My walls are old pine paneling(togue/grove), cement floor with carpet(no pad), drop acoustical ceilings.
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#1647400 - 04/02/04 02:03 PM
Re: Phil Cramer's Bass Trap Design Questions
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Ethan Winer
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Registered: 06/12/00
Posts: 5470
Loc: New Milford, CT, USA
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Jim,
> Can you back these with MDF board panels to make them more mobile? <
Yes, absolutely. Just be sure to use thick MDF and, better, also glue some wood cross bars every two feet to make them even more rigid.
> Are the mid/high traps mid/high bass or mid/high freq <
The 1/4-inch plywood traps absorb low bass, the 1/8-inch plywood traps absorb the high-bass, and the fiberglass-only panels absorb mids and highs.
> And how many for a room 20'd x 14'w x 7'h? <
I've gotten the best results by lining the entire room with them, alternating the types and making sure the wood panels are in the corners. Just as shown and explained in my article.
--Ethan
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#1647401 - 04/02/04 03:23 PM
Re: Phil Cramer's Bass Trap Design Questions
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SlimJim
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Posts: 6
Loc: Washington, DC
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Are the 1/4 and 1/8 Bass traps sealed air tight altogether, both sides?
Let me get one more thing straight, I should line all the walls with alternate traps low bass, high bass and mid/high absorbers?
What do you think of countercarpet ceiling traps?
I plan on stuffing insulation into space above drop ceiling. Then, having every other tile a trap using 703 in a framed box with pegboard exposed down. What do you think?
Thanks in advance, Ethan.
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#1647402 - 04/02/04 05:05 PM
Re: Phil Cramer's Bass Trap Design Questions
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Ethan Winer
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Registered: 06/12/00
Posts: 5470
Loc: New Milford, CT, USA
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Jim,
> Are the 1/4 and 1/8 Bass traps sealed air tight altogether, both sides? <
Yes, exactly as explained in the article.
> I should line all the walls with alternate traps <
Yes, exactly as explained in the article, and as I also suggested two messages above.
> What do you think of countercarpet ceiling traps? <
I never heard of that. What is a countercarpet ceiling trap?
> I plan on stuffing insulation into space above drop ceiling. <
Good plan. The more you pack up there the better.
> every other tile a trap using 703 in a framed box with pegboard exposed down. <
Why make a framed box? And why pegboard?
--Ethan
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#1647403 - 04/02/04 06:07 PM
Re: Phil Cramer's Bass Trap Design Questions
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SlimJim
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Posts: 6
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In a book: How to Build A Small Budget Recording Studio From Scratch by Michael Shea, Shea explains that carpet is a poor aborber of low bass freq. So, to counter act the carpet one needs to have thick 703 in the ceiling space. Built by sealing a framed box on all sides except the side exposed to the room. This side gets peg board and cloth to cover the pegboard. The 703 should be against the peg board with an air gap between the 703 and the top MDF above.
What do you think? Shoot as many holes in this as you like. I would rather not waste time and money if I don't have to.
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#1647404 - 04/02/04 10:39 PM
Re: Phil Cramer's Bass Trap Design Questions
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Andre Vare
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Registered: 03/13/04
Posts: 125
Loc: Hamilton, ON Canada
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Scratch the pegboard.
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#1647405 - 04/03/04 11:45 AM
Re: Phil Cramer's Bass Trap Design Questions
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Ethan Winer
MP Hall of Fame Member
Registered: 06/12/00
Posts: 5470
Loc: New Milford, CT, USA
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Jim,
I agree with Andre that pegboard is not useful here, and is actually harmful in a typical home studio with a low ceiling. See the sidebar "Hard floor, soft ceiling" in my Acoustics FAQ.
--Ethan
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#1647406 - 04/09/04 01:48 AM
Re: Phil Cramer's Bass Trap Design Questions
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Light Farm
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Registered: 04/06/04
Posts: 3
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> Can you back these with MDF board panels to make them more mobile? <
Yes, absolutely. Just be sure to use thick MDF and, better, also glue some wood cross bars every two feet to make them even more rigid.
Thanks.
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#1647407 - 04/09/04 02:16 AM
Re: Phil Cramer's Bass Trap Design Questions
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Light Farm
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Registered: 04/06/04
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> how important can be the thickness of this back wall and how steady does the trap have to be mounted to the wall <
The back needs to be rigid enough not to flex. If you use at least 3/4 inch plywood, MDF, or particle board, it should work okay. It does not have to be mounted securely to the wall, but it must rest against the wall. Wood panel traps do not work well when spaced out from the wall. So make sure the back is right up against the wall.
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#1647408 - 04/09/04 01:05 PM
Re: Phil Cramer's Bass Trap Design Questions
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Ethan Winer
MP Hall of Fame Member
Registered: 06/12/00
Posts: 5470
Loc: New Milford, CT, USA
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LF,
> If the bass traps ... with a couple of angle brackets <
Then you might as well just build them onto the wall as shown in the original plans.
--Ethan
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