Not to resurrect an old conversation, but my basement/place my wife fears to tread is unfinished. Anyone have any thoughts on the right insulation to run in between the ceiling joists to best create a sound buffer?
Thanks
Yes.
Insulation between the ceiling joists works best in the room itself as a sound absorber for mid and high frequency reflections, or, if dense enough, lower frequencies, but only if there's fabric to allow sound to pass through for the ceiling insulation to absorb.
Good for your recording room, however, that does very little for the rest of the house. You won't solve much, if anything with insulation. Maybe a couple of db.
If, however, you want minimum transmission
into the rest of the house, you're better off with an air pocket and double-thickness drywall, separated from the joists themselves with vibration absorbing rubber mounts, such as the ones available from ASC. Plan on float-mounting a floor as well, and isolating the walls with the same rubber mounts.
There's no real way around this. It's purely physics.
You want to prevent the upstairs floor, and the frame of the house, from vibrating and transmitting sound. That takes mass and isolation.
The structure-borne vibrations are the worst culprit, and need to be isolated. That is, the pressure on the ceiling, walls, floor, etc., that vibrates the rest of the house needs to be controlled. Soundproofing is based mostly on mass and isolation, not absorption behind ceiling panels or drywall. Air is an effective barrier, provided there is enough mass in the noisy room, plus isolation.
Sorry to be the bearer of bad tidings.
There's a lot of information in the F. Alton Everest handbook on acoustics. Trust me, you'll be depressed once you read it, unless you plan on spending a lot of money.
Incidentally, foam does nothing for lower frequencies, and those frequencies are the thing that vibrates walls, floor and ceiling, and creates the boom-boom-boom you hear when someone upstairs is listening to music at high volume.
On the cheap, you can reduce the amount of bass transmitted to the structure with something like the isolation platforms like the Gramma 2 offered by companies like Auralex, but they will only reduce structure-borne vibration, not eliminate it.
This is my 32 years of experience in the studio business talking. True soundproofing isn't only an art, it's a very, very
expensive art.