Soundproofing Question

[gdgross]

I posted this in the 'newbies' forum, but thought I'd go for a re-post here, too.

Hi folks, I am new to the forum. I posted the following on a couple of guitar sites, but thought there might be some better advice here, too.

I'm planning on converting a room in my home to a recording/mixing/rehearsal room. It'll be used for electric bands as well as acoustic & classical recording/rehearsal to give you some idea of volume. There are three exterior 2x4 walls and one shared wall with the garage. The room is 10x14 with 8' ceilings and a concrete slab floor. I want to maximize every sqaure inch of floorspace, so a room within a room is pretty much out.

I had planned on pulling down the interior drywall from the walls and adding rockwool insulation, (the walls currently have no insulation whatsoever) then doing a drywall/sheetmetal/drywall sandwich on top. But a friend recently suggested to instead fill the walls with sand.

Sonically, would sand be better than fiberglass or rockwool insulation in terms of isolation? There isn't as much trapped air, but it's a lot more dense.

Practically, I am worried about the weight of the sand on the outside stucco. (On the inside I could use 3/4" plywood underneath the drywall for extra strength.) I'm also worried about keeping moisture out and what happens if it gets in. I can run all kinds of extra counduit and junction boxes before I close up the walls, so I won't have to cut into them in the future and have sand spill all over the place.

Your thoughts are much appreciated!

 

[Farview]

Use resilient channels and double up the drywall. stud>drywall>resilient channel>drywall. use the thickest drywall you can get.

 

[Bulls Hit]

What's been recommended to me is to mount the resiliant channel onto the studs, then 2 layers of different thickness drywall onto the RC.

Stud > RC > Drywall 1 > Drywall 2

Fill the wall cavity with accoustic batts insulation. (no sand!)
Don't let any of the drywall screws hit any of the studs. Don't let the drywall touch the floor or ceiling or drywall on other walls. Caulk all joints between drywall & floor/ceiling/other drywall with accoustic sealant on both layers

 

[jkvd]

I agree with the above.

The more weight, the better the insulation. If you go for double layer off drywall, glue it on crossed to avoid leaks between the plates.

The trick is that the soundenergie is transferred into a heavy material that is not stiff. That's why the mounting on Resilient Channels. The edges need the same flexability so there you use caulk. Of course all needs to be airtight!

Here are some pictures:
http://www.auralex.com/sound_isolation_rc8/rc_discussion.asp

Much of the soundproofing quality depends on you buildingskills =)

 

[gdgross]

Thanks guys. Based on the advice here and on other forums (especially the recording studio design forum) I have decided to ditch the sand and go with more orthodox methods of soundproofing.

First I'll be tearing down the existing drywall, and caulking and insulating with rockwool. Then comes 2 layers of dryall (one 5/8" layer and one 1/2" layer mounted on resilient channels.) This will be the same for both walls and ceiling.

Next I will be floating the floor, but I do need to figure out exactly how many neoprene pucks or auralex uboats I'll be using.

Last part will be the windows and door. Any suggestions for good, high STC, commercially available windows? I don't want to frame my own, as these windows will be the only ventilation in the room (no HVAC) so I need ones that can open and close.

Thanks!

 

[Bulls Hit]

For windows, the best bet is laminated glass rather than double glazing, and nice rubber seals around the opening

 

[crosstudio]

if you've got 8' ceilings and you float the floor your going to have a very low ceiling.

are you laying the studs flat on the neoprene?

btw, you should have put this thread in the studio design forum. you'd probably get more hits.

 

[Cloneboy Studio]

Try to have space between the studs/walls and existing walls in addition to insulation. Sound vibrates through solid objects readily--air pockets help to combat that.

 

[steve grimm]

Try

I've used rubber sheets, like the ones used for truck bed liners, glued to partical board for the inside of my walls. But then I found out about MDF from a different forum that I read. MDF is Medium Density fiber board and I'm real happy with this stuff. It comes in 1/2" or 3/4" 4x8 sheets the 3/4" sells for around $24.00 a sheet. I made a wall for my control room using this on both sides of a frame of 2x8's and I'm really, really happy. Oh yeah I dampened the recording room using the stuff they use to partition office space,
A friend found it used at an office supply store for next to nothing and it works great!