Double width studs for isolation?

Schipo, I always tell people that every medical class has someone who graduated last, and that person just might be THEIR doctor.

Anyway, builders of townhomes with shared walls often put a "double" or "staggered" wall between units to minimize sound transmission.

If you put some fuzzy stuff between the studs, companies such as Roxul or Corning make insulation with sound absorbing properties. You can find it at Home Depot.

Also, I've never seen it in a store, but on some home reno shows on HGTV, I've seen a new type of sound absorbing drywall. It's a bit expensive. I believe it has a sheet of metal sandwiched between layers of gypsum. It might work through the stiffening effect that Nsgach noted. Maybe you can find it somewhere. Try the websites for drywall manufacturers.

Eldartford is correct about the styrofoam stuff having to be covered to avoid fires. I'm finishing my basement and I'm looking at adding styrofoam or polystyrene panels on the wall as a thermal break and for insulation. The panels all say that they need to be covered with something because they are flammable. The building code where I live requires covering as well.

I'm not smart enough to go to MIT. Maybe some of what I'm saying is true anyway.

One of the principles of reducing sound transmission through a wall is to add mass. Unfortunately, walls are already heavy, and to make a big improvement you have to add a lot of mass.

According to the greengluecompany.com which has done these kinds of tests in independent laboratories, "to improve sound isolation by about 10db you would have to quadruple the number of drywall layers on your wall - from one each side, to four on each side." Adding mass combined with other methods is far more effective.

I suspended a ceiling consisting of 2 layers of 5/8 drywall with Green Glue in between and suspended on sound clips, and achieved over 35 db reduction in sound in the room above. I highly recommend you read the their entire web site before making your decision.

Staggered/double studs plus 2 layers of super-dense drywall (Firewall) both sides as well as fibreglas internal insulation will give the best sound-insulation for the adjoining room. This sound-insulation is called STC (Sound transmission Class) Rating. Compared to a normal drywall with say 37 STC rating, the described wall can double the sound-proofing capabilities up to 60 STC.
STC Ratings
Study Diagrams

I've been seeing ads from a company offering rolls of sheet vinyl. They suggest covering your inner walls with the stuff prior to covering with sheet rock.
Sounds good to me...

Correction.....I am getting old!?
STC Ratings are in Decibels (dB) and thus are logarithmic.
Therefore the improvement of 37STC to 60STC is more than a TRIPLING in acoustic performance.