I'm building a music studio in my basement, and my goal is to isolate it
as much as possible (at reasonable cost) acoustically, both to keep
sound from leaking in during recording, and (more importantly) to keep
loud instruments (like drums) from seriously bothering the rest of the
house.

I already have a rough idea of how to deal with the walls: staggered
2x4 studs on a 2x6 baseplate, so that the outer and inner drywall aren't
acoustically coupled via the studs, cavities filled with a heavy
insulating material of some kind (suggestions?)

The ceiling is another story -- I could imagine suspending some kind of
false ceiling slightly below the joists and packing some kind of loose
and relatively dense material above that, but what? And how should the
false ceiling be constructed and suspended in order to give me the best
bang for the buck? Things I ideally want to avoid, by the way, are
insulating materials that are flammable or that contain nasty rock or
glass fibers. Maybe some kind of flame-retardant cellulose pulp?

Also, there are heater ducts all over the basement ceiling, and it would
be nice to figure out a way to keep these from piping sound between the
studio and the rest of the house, without actually having to relocate
them. I'm guessing that if there is no actual opening from a duct into
the studio itself, then packing insulation around a duct will help keep
it from transmitting much sound out of the studio. Comments?

Last but not least, cost *is* an object -- I'd rather have 90% sound
reduction for $1000 extra than 99% for $5K extra.

thanks,

Grant