You lumped me in the company of John Sayers?
I'm honored!
Ausrock was right about staggered stud. More simply put, the idea behind it is that the exterior wall doesn't touch the interior wall (except at the base and top plates), thus minimizing sound transference from the outside to the inside.
You use a 2x6 base plate, and set 2x4 studs on one side of the 2x6 at 16" O.C. Then you set 2x4 studs on the other side of the base plate but these are offset or staggered 8" from the first set.
It makes for a REALLY HEAVY wall section because you have wider base plates, and twice as many studs.
It took 3 of us to tilt up a 10'x10' wall section, position it over the foundation anchor bolts, and plumb & brace it into position. And that was with no sheathing on it.
The theoretical STC for a wall section like this is 61 with a tripple layer of sheathing/sheetrock on each side and insulation in the cavity.