sound proofing 2x4 existing interior wall

[mart]

What would be more effective: Another layer of dryall and green glue or acousti-seal on 1 side or filling the wall with cellulose? Studs are NOT offset. Thanks

[hallerb]

minimally expanding closed cell foam, and perhaps a additonal layer of drywall on those floating supports.

[larry moe 'n curly]

The likely most effective solution is screwing horizontal metal acoustical channels to the existing studs and screwing another layer of drywall to those strips, first making sure to seal all air leaks, including any around wall outlets (you don't want any one stud cavity to have outlets for adjacent rooms). This actually gives a higher acoustical STC rating than a wall made with offset studs. Just adding another layer of drywall won't help much. I probably wouldn't use cellulose because it's messy, compared to fiberglass batt.

[ransley]

What amount of soundproofing do you need, none of those ideas do anything like additional floating walls music studios have.

[ransley]

Have you used foam and know it works, I used foam board on the outside and it Magnified certain sound frequencies that now sound like there are inside the house. Hit a piece foam it resonates loudly, the objective of insulation is to absorb energy I know drywall works.

[Jon Danniken]

Not much gets through a couple layers of 30 pound roofing felt.

Jon

[hallerb]

foam STOPS air inflitration that carries most noise, probably best to gut the wall install acoustic drywall on one side, install spry in foam, then install the remaing acoustic drywall.... drywall on floating mount appears better too

[Reno]

mart wrote in news:pan.2010.07.15.03.54.02.541000 @nowherexcv.net:

Sound-proofing requires more mass to absorb the sound energy so another layer of acoust-seal is best as it is the heaviest material. Sound can also leak around or through walls sort of like water so sealing gaps can help a lot, too. Use an acoustical foaming product.

[sligoNoSPAMjoe]

A lot depends on on the situation, the sound source etc.

Make sure all air to air leaks are corrected. Heating and cooling ducts and returns can allow a lot of sound through. Double walls with no connection from room to room works well.

In some situations the best solution may be to attend to the source. The point is, someone with experience can do far more than all of us here who can't see or hear the situation.

[ransley]

Sound travels and stopping air doesnt stop sound. Have you put foam on your walls to test it, have you build or worked in music studios and have a knowledge of sound, I do. As I said foam will do nothing in certain frequencies and in my place makes certain sounds seem louder, soft materials or materials that absorb work best