Soundproofing a practice room

Hi all, I'm preparing to finish off an interior basement space for use as a music practice room. I've been searching through all the great info on this board for a few weeks now and think I know the best way to proceed but would appreciate any review of my plans by those with more experience. Here's the basics - this is currently an unfinished space, 13' X 17' surrounded on all 4 sides by 10" thick cement walls, except for a 3' wide doorway and a 5' wide 'closet' opening. This opening will be framed down for a 30" door. I've attached a crude sketch that shows an overhead view. Here's a couple of pictures of the space; The room will mainly be used as a practice area for electric guitar and as a small personal studio / hi-fi room. So there's no drums and bass to contend with and the volume won't be that excessive, but most of my available play time is when the rest of the family is asleep, so the more I can do to soundproof this space the better. I think the 10" walls have sufficient mass that I will be able to get away with just attaching studs directly to the concrete, one layer of sheetrock and foam board insulation. I plan on isolating the wall studs from the ceiling. The thickness of the walls also allows me to do a nice dual door airlock, so my only real concern is sound transmission through the ceiling. The floor overhead is just 3/4 plywood subfloor and 3/4 oak hardwood - no carpet. I would have liked to beef up the mass of this floor by attaching two layers of gypsum with GG to the underside of the subfloor, but the hardwood staples will make that very difficult as the following picture illustrates; I've read some of the threads about using foamboard in cases like these to create a nice level surface to apply gypsum to, but I'm not sure with my volume levels that I'll need it. I'm thinking ISOMax or RSIC clips attached to the rafters with hat channel and 5/8 / GG / 5/8 should go a long way for my needs. Any input on this? Which brings me to insulation - I don't mind spending extra on insulation if it will help, but most of the 'acoustic' insulation (i.e. quietzone) I find only comes in 3 1/2 thicknesses or so.... my rafters are 9 1/2" deep. Should I be putting in multiple layers of acoustic insulation? I do want to fill that cavity completely, correct - no air gap? Should I do like 5 1/2 of regular pink and 3 1/2 of acoustic? Should I overstuff it, to like 10 or 10 1/2 of fill and them compress it with my gypsum? If that's the case I guess I'll need to consider the depth of the ISO clips and hat channel and increase it by that much more. Insulation is one thing I've really not been able to find a lot about. So, any advice or comments are appreciated. You've got a great site here! Randy

Randy, Greater mass on the ceiling will help stop the transference of sound to the level above. You could insulate the bays and install RC on the bottom of the joists and then Install 5/8" drywall on that. You could even double layer it with 1/2 " and 5/8" for more mass. It really depends on the SPL you'll be working at. I think the concrete floor and walls are going to want o project the sound upwards (the path of least resistance.) I would frame out the walls of the new room stood off the concrete walls with steel studs. You can also decouple the wall from the floor and ceiling for better isolation. It should help a bit. Fastening to the concrete walls with 1x or hat track would keep the wall very rigid and not help much. For Isolation you may want to build a room within a room. There's are many topics on it. Steel studs are pretty easy to work with. You could also box in every few bays, install 703 or rock wool and cloth cover them to help trap sound. Like a built in book case. If you decide to sell the house, take the cloth and insulation out and install shelves in the box and call it a library. Or make units that fasten to the wall to trap some of the sound. You'll need absorption to aid you in trapping the sound of music. Just sealing off a room isn't going to do it. The sound will build and become destructive amongst itself and it will sound bad as a result. I forget a lot of what I read here, but these are just some of my thoughts from reading here for a few years. There may be better ideas too. HTH :D You could also do something like this on your ceiling: http://www.johnlsayers.com/phpBB2/viewtopic.php?t=9834 I just put this in a resturant for trapping noise.

Randy K wrote:

I've read some of the threads about using foamboard in cases like these to create a nice level surface to apply gypsum to, but I'm not sure with my volume levels that I'll need it. I'm thinking ISOMax or RSIC clips attached to the rafters with hat channel and 5/8 / GG / 5/8 should go a long way for my needs. Any input on this?

I've done this in my basement. That is, with nails protruding down through the sub floor from the tile work above in the bathroom, I placed foam board up between the rafters. I only did this so I had a level surface to then place drywall layers (2) over the foam section. In my example the nails didn't run the length so I have simply overlapped the drywall excessively to prevent any weak spot of that mismatch in thickness or where the drywall is placed. This is what it looked like after putting up the foam - But, in re-reading your post I see you're thinking of not even doing any of the work in between the joists... You've said a few things in your post there that you may want to think about -

Randy K wrote:

The room will mainly be used as a practice area for electric guitar and as a small personal studio / hi-fi room. So there's no drums and bass to contend with and the volume won't be that excessive, but most of my available play time is when the rest of the family is asleep, so the more I can do to soundproof this space the better.

Think a bit about the chances there will be a day that you do wish to have a band play along with you in this space and whether you'll be thinking the woulda/coulda/shoulda routine about beefing up the Mass on the deck or the first layer of the MAM. It is the most tedious part of the process that I have found - all the cutting of drywall, placing of backer rod, caulking... The time taken in these steps can be long. Buy rod's book that's referenced around these posts... It's a great read on things like this and deals with ways to think about how effective the steps you'd take can be.

Thanks for the comments guys! Zartler - you're right, I'll really need to think about the acoustics in this space - between the rigid walls and rectangular shape it will need some attention. Once I have a finished room I'll dive into that with strategically placed absorbers like you did in your restaurant application. Cram - it was your thread that got me thinking about trying the rigid foam approach. I'm still debating it, but am leaning towards taking my chances with the ISO clips and 5/8 / GG / 5/8. Unfortunately, the entire ceiling in this room is covered in these staples, which protrude 1" or so. That's 170 linear feet of 16" O.C. bays. A LOT of work to foam board, backer rod, caulk and do 2 layers of gypsum with GG. Your point about future uses for this room is well taken, but honestly it's not large enough to accomodate a drummer, so if that situation were to arise I'd need to take other measures anyway. I've decided to use double 5 1/2" OC Quiet zone batts in each bay. With a total fill of 11", there will be some compression of the insulation which should help.