#1900107 - 02/27/08 08:20 PM
Hanging panel traps
|
dogster
Member
Registered: 02/27/08
Posts: 18
Loc: Sydney, Australia
|
Offline
|
|
Hiya
I'm about to set up a room with traps and absorbers, but I need to build a frame on which to hang the traps and materials, ie I can't affix anything to any of the walls or ceiling area without incurring the wrath of the Body Corporate.
My question is with regard to panel traps - if they are to be mounted on a frame instead of a wall, what should I use as the back of the panel trap ? 12mm MDF perhaps ?
Also, what happens if you alter the measurements of the traps, so that they are something other than 2' x 8' (as in your article Ethan). Say 1500mm x 900mm (approx 3' x 5') ?
Cheers,
Stewart.
|
|
Top
|
|
|
|
|
#1900339 - 02/28/08 08:41 AM
Re: Hanging panel traps
[Re: dogster]
|
Ethan Winer
MP Hall of Fame Member
Registered: 06/12/00
Posts: 5406
Loc: New Milford, CT, USA
|
|
Offline
|
|
If you can't attach traps to the wall I suggest you not bother with wood panel traps at all. Just use rigid fiberglass as described in the Forum FAQ.
--Ethan
|
|
Top
|
|
|
|
|
#1900657 - 02/28/08 04:10 PM
Re: Hanging panel traps
[Re: Ethan Winer]
|
dogster
Member
Registered: 02/27/08
Posts: 18
Loc: Sydney, Australia
|
|
Offline
|
|
Hi Ethan,
Thanks for your reply.
Does that mean a panel trap won't work as a self-contained unit ? I was thinking of building a "room within a room", where the panel traps effectively become the walls and / or ceiling.
Cheers,
Stewart.
|
|
Top
|
|
|
|
|
#1900692 - 02/28/08 05:40 PM
Re: Hanging panel traps
[Re: dogster]
|
Ydope
Senior Member
Registered: 03/02/07
Posts: 89
|
|
Offline
|
|
Does that mean a panel trap won't work as a self-contained unit ? I was thinking of building a "room within a room", where the panel traps effectively become the walls and / or ceiling.
The backs of the panel traps will still let a lot of bass through which won't get absorbed. Once you make them so thick, that they are as rigid as real walls, they'll weigh a ton.
|
|
Top
|
|
|
|
|
#1900843 - 02/29/08 04:50 AM
Re: Hanging panel traps
[Re: Ydope]
|
dogster
Member
Registered: 02/27/08
Posts: 18
Loc: Sydney, Australia
|
|
Offline
|
|
So, how thick would the backs need to be, to be effective ? Weight in floor-mounted devices doesn't present a big problem for me, but depth might cause some headaches.
As for ceiling mounted traps, does the bass normally dissipate into the roof cavity ?
S.
|
|
Top
|
|
|
|
|
#1900927 - 02/29/08 07:23 AM
Re: Hanging panel traps
[Re: dogster]
|
Ethan Winer
MP Hall of Fame Member
Registered: 06/12/00
Posts: 5406
Loc: New Milford, CT, USA
|
|
Offline
|
|
You can make a panel trap with a back, but then it's even heavier and more effort to build. At that point it makes more sense to use fiberglass-based traps.
--Ethan
|
|
Top
|
|
|
|
|
#1901730 - 03/01/08 09:29 PM
Re: Hanging panel traps
[Re: Ethan Winer]
|
dogster
Member
Registered: 02/27/08
Posts: 18
Loc: Sydney, Australia
|
|
Offline
|
|
Thank you for your posts gentlemen.
OK, you've nearly talked me out of it Ethan.  I've read your Acoustic Treatment and Design article thoroughly (twice - excellent document BTW) and I really like the concept of panel traps, as it seems that the only other practical way to get effective broadband bass trapping is with very thick rigid fiberglass spaced well away from the walls, which would encroach a long way into my control room area.
I had planned to just put up some screens around the room made out of 6mm MDF with 50mm fiberglass or rockwool on the back and 50mm acoustic foam on the front, then spaced say 50mm from the walls - but I'm now suspicious about how effective that would be in the lower frequencies and whether that would just create a big boom-box of a control room.
I work full-time from home doing music production and have designed and constructed a purpose-built isolation booth for recording purposes - it weighs about 800kg (I hope I never have to move that thing again  ). I have a bunch of Auralex foam (a D240 kit) that I will use to control the mid and high frequencies, but don't yet have a solid plan for bass trapping.
I plan to stay in the new place (just bought a few months ago) for a long time so I have a "blank canvas" on which to set up my studio for the long term, so I would like to extract as much performance out of it as possible. In short, I don't mind doing the hard yards (eg building heavy floor-standing panel traps) as I don't really have the budget to employ professionals to come in and set up my room for me. Besides, all this learning and application of the theory is fun ! I am considering building a steel frame inside the room on which to hang all my sound control stuff, and I would make it as strong as it needs to be to support whatever weight it is to bear. If I went to those lengths, I'd probably incorporate a Faraday Cage into the construction to take care of any external RF interference. (It's a long term project.)
So that's the background behind these queries:-
1) How thick would the back panel of a free-standing panel trap really need to be ?
2) Would the performance of any panel trap be improved by
a.using thicker and / or more dense fiberglass
b. increasing the dimensions of the box ?
3) Can the range of frequencies over which a panel trap is effective be extended by making a wedge-shaped box ie 3" deep at one end and 6" deep at the other ?
4) Would a panel trap still be effectively trap bass if acoustic foam was positioned in front of it (presumably not actually touching the front panel of the trap itself) ?
Also, I have sketched up a plan of my studio as it is right now, do you have any other suggestions that might help me in my quest for The Perfectly Flat Room ?
[img]http://img89.imageshack.us/my.php?image=studiolayoutwithmeasurepn8.jpg[/img]
One other query, does a panel trap or Helmholtz device need to "see" the speakers to be effective - ie can it be placed elsewhere in the room ? The attached drawing of the studio layout will explain why I'm asking this. What about placing a resonance trap under the sofa, for example ?
Thanks heaps,
Stewart.
|
|
Top
|
|
|
|
#1901832 - 03/02/08 07:51 AM
Re: Hanging panel traps
[Re: dogster]
|
Ethan Winer
MP Hall of Fame Member
Registered: 06/12/00
Posts: 5406
Loc: New Milford, CT, USA
|
|
Offline
|
|
Stewart,
I really like the concept of panel traps, as it seems that the only other practical way to get effective broadband bass trapping is with very thick rigid fiberglass spaced well away from the walls, which would encroach a long way into my control room area.
That's not necessarily true. The low-bass trap peaks around 100 Hz, and 4 inch thick rigid fiberglass or mineral wool is also pretty effective at those frequencies when placed in corners. In a smaller room like yours you really are better off with fiberglass traps.
6mm MDF with 50mm fiberglass or rockwool on the back and 50mm acoustic foam on the front, then spaced say 50mm from the walls
A sandwich of absorption with MDF in the middle won't work very well.
1) How thick would the back panel of a free-standing panel trap really need to be ?
3/4 inch or more.
2) Would the performance of any panel trap be improved by
a.using thicker and / or more dense fiberglass
b. increasing the dimensions of the box ?
Bigger absorbs more.
3) Can the range of frequencies over which a panel trap is effective be extended by making a wedge-shaped box ie 3" deep at one end and 6" deep at the other ?
No.
4) Would a panel trap still be effectively trap bass if acoustic foam was positioned in front of it (presumably not actually touching the front panel of the trap itself) ?
Yes.
does a panel trap or Helmholtz device need to "see" the speakers to be effective
No.
can it be placed elsewhere in the room ?
Bass trap work best in corners, and also flat on the front and rear walls. But all locations are at least a little useful.
--Ethan
|
|
Top
|
|
|
|
|
#1902247 - 03/02/08 08:08 PM
Re: Hanging panel traps
[Re: Ethan Winer]
|
dogster
Member
Registered: 02/27/08
Posts: 18
Loc: Sydney, Australia
|
|
Offline
|
|
Thanks for your much-needed help Ethan.
While sourcing fiberglass, I've found that Owens Corning don't distribute here in Australia. There are of course equivalent products from other manufacturers - for the foil-backed fiberglass am I looking for a perforated backing or the non-perforated kind ?
Actually, even after reading up on fiberglass absorption, I'm still not sure whether I need foil-backed for corner-placed panels. Is the foil-backed variety recommended for corners, whether across 2 vertices or 3 ? I'm thinking I'll start with big thick panels (at least 600mm square x 100mm deep) across the tri-corners and then start measuring the results, and install panels along the length of the wall-ceiling corners as required.
Thanks again,
Stewart.
|
|
Top
|
|
|
|
|
#1902465 - 03/03/08 08:12 AM
Re: Hanging panel traps
[Re: dogster]
|
Ethan Winer
MP Hall of Fame Member
Registered: 06/12/00
Posts: 5406
Loc: New Milford, CT, USA
|
|
Offline
|
|
I've never seen perforated foil. You want solid foil on all corner traps, and no foil for panels at reflection points.
|
|
Top
|
|
|
|
Moderator: Ethan Winer
|
|
|
