Side wall absorber

Hi everyone! I'm thinking about building a side wall absorber in each side of little vocal booth with the dimensions: lenght: 1,5 m, width: 0,7 m and height: 2,1 m. The little room is at this moment isolated 100mm rockwool insulation, wallboards and pyramid foam, but that makes my sound very dark, since this construction only keeps down the high frequencies - not something I prefeer. So I need a new construction, that can help me keep down all the frequencies and give me good acoustic for recording vocals. I have three questions pertaining to this: 1. Is it even a good idea to use this construction(side wall absorber) in such a small room? 2. Is it okey of the wall is only displaced 100mm instead of 200mm, since I do not have that much space? 3. How do I make sure that the unit is air sealed correctly? I should might add that I have no possibility of changing the dimensions of the room.. :( Hope that some of you can help me with this, and that way help me to get a better studio :D - Magnus

Would it be possible to remove the pyramid foam and wallboard from the inside walls? If isolation is not a problem, you could then frame up a "thickness" extender so your total wall thickness would be 200mm (100mm where the rock wool is now and 100mm with the new wall. Then stuff the entire cavity you've created with rockwool and cover the walls with cloth. If isolation IS a problem, you could also remove the rockwool and "beef up" betwen the studs of the outside walls (from the inside) like Sharward did on his garage (maybe two additional layers of 5/8" drywall calked against the studs), build out the new extender framing, and put the rockwool back and continue as above. Just a thought. len

Thanks for your answer! Do you believe that the first solution you suggested would be much better than building the side wall absorbers? If I use your solution, won't my room be very dead then? Finally, I'm afraid, giving the average size of my room, that 100mm extra isolation will make the room too small :) Anyone who has any objections on building the side wall absorber in such a small room?' Thanks again :)

With that narrow a booth, if you don't need much isolation but DO need better sound, I'd be tempted to remove the inner wallboard altogether; then put your insulation flush with the frame and cover with cloth. Before covering, try out the sound and if it's too dark you can first cover parts of your insulation with light gauge plastic (about .05mm) until you like the sound, then cover with cloth. If you're concerned with damaging the cloth or insulation in such cramped quarters, you might want to find some fairly open metal mesh to fasten across the face of your frames... Steve

Knightfly wrote:

With that narrow a booth, if you don't need much isolation but DO need better sound, I'd be tempted to remove the inner wallboard altogether; then put your insulation flush with the frame and cover with cloth.

It's nice to know I finally got SOMETHING right. It seems like I lost my "touch" there for a while. That is assuming I ever had one! Steve - How "open" are you talking about with the perforated metal? Like Masonite pegboard, window screen, or something in between? Len

Len; ya still got it (whatever "it" is :wink: ) - I meant something "in between" - screen isn't strong enough for much protection, and peg board would make a helmholtz effect at probably the wrong frequency (too lazy to calculate :oops: ) - more like this stuff http://www.marcospecialtysteel.com/expandedmetal.htm may be difficult to find locally, unless you have a bulk steel supplier handy... Steve

I would really like to know, whether or not it wuld be an good idea for me to built the side wall absorper?:D I shoudl I go with your other suggestions? :D

The answer is dependant on how comfortable you feel with having ALL of your walls covered with fabric or just a panel or two (that might not extend all the way to the floor. Given your limited space, if it were me, I'd use the "inside-out" wall approach and forget the side wall absorbers (because they will be "built-in" the wall itself. How much isolation you need is also something you have to consider. Sorry I can't make the decision for you on this one. len

Since I will not be able to build on the outside of the booth, I actually think I'm gonna go with the side wall absorpers. I only have one last question then: how do I make sure that the unit is air sealed? :shock:

Seal the back all the way around with acoustic calk. That should do the trick. len

Im not sure I'm familiar with that material... Is there any way you could rephrase? I'm from Denmark :)

Sorry for the long delay in replying. Acoustic calk is like regular calk that you use around windows and such to seal it but it doesn't really ever dry out. It provides an air-tight seal between two surfaces. len