Spray Painting Sound Foam?

E

elil

New member
I've been messing around with acoustics and soundproofing for about 6 years or so. I've worked on several "studios" over the years, and have finally constructed my final home practice space/recording studio (Airtight room, w/ concrete walls filled w/ sand, decoupled from sheetrock on both sides, and non-reflective s-shaped ventilation = -80db sound reduction!).

This whole time, I've been using the same sheets of sound foam for acoustics and they've gotten a little beat up from all the moves, etc. I've just about tapped out my resources on gear and building materials and I would hate to throw away all of this good working foam; however, I want it to look good too. Does spray painting sound foam reduce it's acoustic properties significantly?
 
It's very difficult to paint it without clogging up the pores.

Consider making fiberglass panels with fabric covers. Remember the Great White fire? I hate seeing a bunch of that stuff on a wall.
 
There is a company that covers their panels in cloth, with a bunch of colors available. I will try to find the name for you.
 
Thank you for your quick replies. Just to clarify, I don't really have the money to invest in new acoustic material. The foam I got was approx 3'x5'x1.5" with this type of pattern:

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It cost around $800 when I bought it and does the job great. There are a bunch of chunks missing and some of the grey "paint" has scraped off of the visible surfaces. I was planning on using a grey spray paint to touch up areas where it was missing.

I figured that this wouldn't damage the sound properties too much, but then I got to thinking that I might as well paint them all a different uniform color.

So apl, you do I understand this right: If I paint the entire surface I could potentially clog all the pores and this would affect the sound properties drastically? Even though the foam has a acoustically textured surfaced? I was under the impression that acoustics had more to do with dispersion of reflections than w/ the type of material.
 
elil said:
So apl, you do I understand this right: If I paint the entire surface I could potentially clog all the pores and this would affect the sound properties drastically? Even though the foam has a acoustically textured surfaced? I was under the impression that acoustics had more to do with dispersion of reflections than w/ the type of material.
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The soundwave sloshes into the foam and the energy is apsorbed. Some acoustic panels are perforated metal with fiberglass inside and the fiberglass is in a plastic bag. In that case, the bag transfers the sound nicely into the fiberglass which absorbs the sound. In the painted foam case the paint and foam together would get pretty stiff and act like a reflector.

Having diffuse reflections is important for good acoustics because it prevents standing waves and resonances. The reason for wedged acoustic treatment has more to do with performance at various angles of incidence than diffuse reflections. Some acoustic treatments (called "cityscapes" or "skylines" because they look like scale model downtown metro areas) intentionally cause diffuse reflections. Like we discussed in another thread, this helps a room have some ambience without resonances.

Actually, that foam is very limited usefullness for frequencies below something like 200 Hz. One way to gain a little extra is to set it away from the wall about the distance that it is thick with something open like chicken wire behind it. This could be framed in and then covered with fabric.

As much effort as you put into isolating the room, you might want to think about putting up the ugly foam and throwing some bales of fiberglass in the corners for some bass trapping for now. Then you can save your pennys and get something like Ethan's room package from www.realtraps.com later. That stuff looks better than any painted foam anyway, and will give you better acoustics, too.
 
Wow, thanks for the thorough explanation!

When I constructed the studio I made sure that there are only two parallel walls, and one of them has a soffit. It did a great job in dropping the bass freqencies and seemed to kill most resonance. I actually have a recliner sitting in the only 90° corner to eliminate any other bass relfections if possible and it seemed to work. The room sounds great live for drum recording, I'm trying to construct lightweight frames on velcro to attach to the walls when using as a practice space to help eliminate some of the live qualities that make it a great drum room. I'm going to try your idea with the chicken wire and probably ferring strips.

However, one question now comes to mind. If the foam is grey on the surface and white on the inside, does that mean that it is painted anyway? I don't expect anyone to know, but does the paint they use work without clogging the pores?

Once again, thank you for all of your insight, it's been very helpful!
 
elil said:
However, one question now comes to mind. If the foam is grey on the surface and white on the inside, does that mean that it is painted anyway? I don't expect anyone to know, but does the paint they use work without clogging the pores?
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That gray film is very thin, light and pliable so the sound wave can easily pass through it. Paint soaking into the foam creates a boundary area that is thick, heavy and stiff.
 
"That gray film is very thin, light and pliable so the sound wave can easily pass through it. Paint soaking into the foam creates a boundary area that is thick, heavy and stiff."

Haha, that's probably why if comes off so easy. Thank you all of your for your help. Unless anybody has suggestions on a thin, light pliable paint I guess I'm stuck with the beat up, rugged look for a while. Have a great weekend everybody!
 
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