Spring-Loaded Screw Turns Drywall Into Sound-Absorbing Panels

I think I saw where they spec'd, for "steel studs", 1 per 8" on stud and every 12" "in the field" (...!) How's that for affordability.

@emailists 
You are correct, the install was probably not done properly. In my slightly over 2700 cubic feet listening room, we used 71 large cartridges of green glue and 21 of sealant. For those who think quietrock is expensive, think again. Conventional double sheetrock/green glue construction verses quiet rock will end up costing you twice as much. But you get what you pay for. On top of that quietrock does not work well in ceiling applications.  In my house of stereo, I can play NIN hesitation marks at 90 dbs and there is zero vibration outside the room. If you love bass and want to keep it inside, there is no compromise. You can see some of the construction process laid out in my house of stereo system. 

Engineering gave us margarine. marketing got people to eat it when animals would not. Engineering gave us synthetic tech fibers that cost half the price of natural fiber cotton, marketing convinced people to pay more money for a product that was cheaper to make and does the same thing. Get the idea here.

I say Quietrock. I built my 2-channel room with Quietrock 545 - more than an inch thick, with embedded sheet steel.

Not cheap - but cost-effective. The quality of the silence is remarkable - actually, most people DO remark on it as soon as they enter. As a bonus, the company is very good to deal with.

It's important to distinguish sound in the listening room from sound transmitted outside it. It's easy to reduce sound transmission by allowing the drywall to flex or otherwise move. BUT that turns the walls into passive woofers moving out of phase with the speakers, and that's not good.

Quietrock solves both problems. Not cheap - but cost-effective.