New Rehersal Space...Need thoughts on Treatment

Posted: Fri Feb 08, 2008 11:44 am

Hey guys,

The band I'm in just leased a big warehouse. It is 20 ft wide 35ft long 20ft high. I just bought Acoustic Foam Corner Kits for low frequencies in the corners, area rugs for the floor to capture most of that sound, and I'm building go betweens to be placed in front of the drums. So that should do it in those areas unless you have further advice.

MY QUESTION is what is the best method for establishing treatment on the walls. The biggest wall is about 580 sq. ft., I have dabbled with the idea of a simple frame around 50% of the wall with carpet attached to it then covered with a durable drop cloth. WE ARE VERY SERIOUS but don't want to spend thousands on acoustic foam. So what is the best method???

Thank you.

Posted: Fri Feb 08, 2008 1:21 pm

The first thing is that if those are the actual dimensions and the room is really rectangular, you will have to do some serious work. The 20x20 dimension means you will have a sequence of double room modes. You can calculate them [quote=http://www.mcsquared.com/modecalc.htm]here.[/quote] Fortunately (as the spammers remind us a few hundred times a day) size matters, and you have a nice large space. That means the room modes are fairly closely spaced, which means a more even response than in a smaller room with the same ratio of dimensions.

Anyway, forget carpet for anything other than the floors. Look for tested products that actually do some bass absorption. Owens Corning 703 and 705 are the DIY products that get mentioned most often. Do a search and you will find links to data on acoustic properties. There are several threads that show walls treated with 2'x4' panels of this stuff put into wooden frames and covered with (flame retardant) acoustically transparent fabric. There are other products that may be more available in your neck of the woods, but I've only used the OC 703.

Posted: Mon Feb 11, 2008 2:28 pm

stephenhatker wrote:

MY QUESTION is what is the best method for establishing treatment on the walls.

Room treatment is a deep subject, and a complete answer requires far more than will fit into a single reply here. So here's the short version. All rooms need:

* Broadband (not tuned) bass traps straddling as many corners as you can manage, including the wall-ceiling corners. More bass traps on the rear wall behind helps even further. You simply cannot have too much bass trapping. Real bass trapping, that is - thin foam and thin fiberglass don't work to a low enough frequency.

* Mid/high frequency absorption at the first reflection points on the side walls and ceiling.

* Some additional amount of mid/high absorption and/or diffusion on any large areas of bare parallel surfaces, such as opposing walls or the ceiling if the floor is reflective. Diffusion on the rear wall behind you is also useful in larger rooms.

For the complete story see my Acoustics FAQ.

There's a lot of additional non-sales technical information on my company's site - articles, videos, test tones and other downloads - linked under my name below.

--Ethan

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