filling walls or not

I framed my booth with 2x4s. Put 2 layers of drywall on the outside, 1 layer on inside. There is nothing between layers of drywall, just air. Then on the interior of the booth, Im putting 4" OC 703 wrapped in fabric. Should I have put insulation between the layers of sheetrock, or is it better to have an air pocket. How will the sound of the booth be effected and how will the isolation be effected. Im thinking it wont affect the sound, but not sure about the isolation.

You should put some sort of fluffy stuff ie R19 in the walls to dampen the resonance of the drywall. It will affect the TL of the wall. -ashley

not to sound stupid, but what does TL stand for?

Isn't stupid at all. I often wonder what people are talking about. TL = Transmission Loss, hence the isolation you search for. TL increases by adding absorption in cavity. :twisted: In Europe TL = R, but that shouldn't have helped you, just writing this.

bassman wrote:

You should put some sort of fluffy stuff ie R19 in the walls to dampen the resonance of the drywall. It will affect the TL of the wall. -ashley

Actually - with 2x4 walls I would use 2 layers of R-13 batt insulation. I would probasbly also add another layer of the drywall to the inside face of wall. I am assuming that you used 1/2" - but the curve woul dbe the same if you used 5/8 - so the percentage of increase in isolation value would be about the same.) The added isolation ( W/ both conditions utilizing 3 1/2" fluffy F>G> insulation) would be as follows: Your wall.................................................w/ added drywall inside 1 single layer of 13 mm gyp board…....single layer of 13 mm gyp board 1.1...................................................single layer of 13 mm type GB 2 90 mm wood studs at 406 mm………….90 mm wood studs at 406 mm 3 90 mm of glass fibre insulation …………90 mm glass fibre insulation 4 25 mm gap filled with air…………………..25 mm gap filled with air 5 90 mm wood studs at 406 mm………….90 mm wood studs at 406 mm 6 90 mm of glass fibre insulation…………90 mm of glass fibre insulation 7 single layer of 13 mm type X G.B.……single layer of 13 mm type X G.B 8 single layer of 13 mm type X G.B.……single layer of 13 mm type X G.B TestID TL-93-271………………………………………… TestID TL-93-272 STC 62…………………………………………………… STC 66 50 Hz 20.0……………………………………………….. 50 Hz 23.7 63 Hz 22.5……………………………………………….. 63 Hz 27.8 80 Hz 28.2……………………………………………….. 80 Hz 32.9 100 Hz 33.8……………………………………………… 100 Hz 38.0 125 Hz 38.0 …………………………………………….. 125 Hz 42.4 160 Hz 43.5…………………………………………….. 160 Hz 49.2 200 Hz 48.7……………………………………………… 200 Hz 54.4 250 Hz 55.8……………………………………………… 250 Hz 60.8 315 Hz 60.8 …………………………………………….. 315 Hz 65.8 400 Hz 65.8 …………………………………………….. 400 Hz 70.1 500 Hz 68.5……………………………………………… 500 Hz 72.7 630 Hz 72.3……………………………………………… 630 Hz 75.4 800 Hz 76.5……………………………………………… 800 Hz 77.9 1000 Hz 80.1……………………………………………. 1000 Hz 81.4 1250 Hz 83.4 ……………………………………………. 1250 Hz 83.8 1600 Hz 87.7……………………………………………. 1600 Hz 86.4 2000 Hz 86.8……………………………………………. 2000 Hz 86.0 2500 Hz 78.1……………………………………………. 2500 Hz 79.4 3150 Hz 78.2……………………………………………. 3150 Hz 79.8 4000 Hz 83.9……………………………………………. 4000 Hz 85.3 5000 Hz 89.1……………………………………………. 5000 Hz 90.3 6300 Hz 90.1…………………………………………….. 6300 Hz 90.7 Note that there isn't much gain at all in the high end - BUT - you have some rreal nice gains in the low end. Test results from IR-761 GYPSUM BOARD WALLS:TRANSMISSION LOSS DATA By R.E. Halliwell, T.R.T. Nightingale, A.C.C. Warnock, J.A. Birta Sincerely, Rod

Not to be niggly Rod, but in your description of the second wall (with added drywall) can we assume you accidentally added an extra layer of stud work and left out some R-13 insulation? :)

Boomka77 wrote:

Not to be niggly Rod, but in your description of the second wall (with added drywall) can we assume you accidentally added an extra layer of stud work and left out some R-13 insulation? :)

Yup - was an error on my part - has been fixed - thanks for picking up on it. Sincerely, Rod