My Studio has steel studs and ceiling joists....... Insulation is stuffed in between all studs and joists, so I get no in-wall reverberation or noise, and I haven't had any trouble with rattling noises....
I have two layers of drywall seperated by a 1" space, all over the room, incl. ceiling....
I was originally worried about the drywall rattling on the steel studs, but it's been over a year and haven;t had any problems.....
If it was steel on steel, that might be a different story, but The back of most drywall is paper, so I think that works as an insulator to rattling noise.
Anyways.. Im not saying mine is "the way", but It works.
http://www.voxvendor.com/thestudio.htm
Be Careful..... It's easy to get too caught up in construction... I know people who have spent years building a studio that they have no recordings or output to show for all the work..
Like I did, slap up a decent room with some strategically placed Deadening/refection material and start recording!..
I know homewreckers who have spent $30,000 on a room.... And honestly, now it's just the wifes office.... In fact, I have seen this a few times..
This is home recording....