Garage Studio/Practice Room

[liqdchris]

I'm in the process of building a rehearsal room/studio in my 2car garage of my single family home in a residential neighborhood. I have a question about the design of the walls and am wondering if any angles in the walls will help, or if certain angles will help better than others to isolate the sound more. Also, if I should float the floor, or if I should just float the drums and amps on their own stages within the new room. Here's the main problem...

The neighbors.

All the neighbors except for the ones next to garage are cool. I just happend to land the luck of the draw and get neighbors who cuss and yell at you if you so much as enter your own back yard. I was forced to cut down 2 50' pine trees and they'll let me practice if I put up a new fence, put a new roof on their house, and a new sewer system in. I just moved in a few months ago too. .... I now have the apropriate licences and permits from the city that will make it legal if I can get to under 50db at the property line, or something you can't hear from the curb accross the street. With the soundproofing I've done so far, it sounds like a stereo playing.

Here's a link to a badly drawn picture of my garage in paint.

Garage Outline

Here's what I have done so far to prep the work.
- North wall: Stucco outside wall, R-13 insullation with 5/8" Drywall. Then I hired a handyman to help work on the garage and he drilled a 2x4 wood stud wall to the existing wall, put another layer of R-13, then drilled soundboard and 1/2" Drywall on that.

- Ceiling: 2x4 studs 24" apart. They are covered with soundboard, then 1/2" Drywall.

- Garage Door: Soundboard on the wooden garage door. Sealed 2x4 Stud box, covering the garage door with soundboard on the garage door side, 2x4 with R-13 insullation, soundboard and 1/2" Drywall.

- House Wall: Regular 5/8" firewall with insullation, on the garage side I drilled soundboard and put carpet on top of that.

****************

I'm thinking of building another room within the left over space because you can still hear the band playing from the outside. The head city code officer is cool and said we're good just as long as you can't hear it from the curb accross the street.

I have 4 bedrooms and one of them is a sepparate music room. I could run a snake up through a wall and attic to that room and make it a controll room if needed. My first concern is to make it soundproof, then if possible, have a decent studio to record in. I'd appreciate any help and advice you could give me.

Thanks,

[knightfly]

Chris, you're in luck - I just happen to be running a special this week

Man and wife, graphically obvious causes with you having un-shakable alibi, think Godfather/horse - $500

Same, apparent argument gone very bad - $1000

Same, apparent double heart attacks - $2000

Same, disappeared no trace - $5000

Kids - brats, no charge honor roll, $500 each...

Seriously, though, I HATE getting these questions AFTER this much has already been done, because invariably it was done knowing about the same as I knew 15 years ago, and it pains me to have to tell people to rip stuff out and start over...

However, before you do that you need to hit the local Radio Shack and buy one of their Analog Sound Level Meters, cost about $45. (Don't forget to buy a 9V battery, and NOT one of their brands)

Get the band together, and if you're the drummer have someone else play the drums as loud as you do, go to the Evil Neighbor property line and measure the sound level. Put the meter on "C" weighting, FAST response, point it at your wall and walk the property line full length of your garage. Note the LOUDEST PEAKS you get. (It wouldn't hurt to clue the "Northern Nasties" in to the fact that you're doing a TEST, not a "SCREW YOU" session...)

This will let you know how much more reduction in SPL is necessary, so we can further get your problem solved.

As to your wall beef-ups, that's the part I was referring to when I said I hate these kinds of questions - even professional builders, unless they have studied sound proofing thoroughly, aren't aware of what works best and what only costs as much or more. Here is the biggest single example - Let's say you are building a wall starting from scratch (just for purposes of explanation) and have the materials to put up two separate stud walls and 4 layers of 5/8" sheet rock, both with insulation -

If you build two identical stud walls 3" apart, both with a single layer of sheet rock on each side of the studs, you will have 4 "leaves" separated by 3 "air" cavities, and an STC rating of about 40 dB, assuming you have everything hermetically sealed with the right kind of caulk.

If you build the same two frames, but move the inner layer of sheet rock to the outside so that you have two layers of sheet rock, studs, 3" space, studs, then 2 more layers of rock (same exact materials, placed different) then you will have an STC rating of about STC 60 - 20 dB improvement, JUST FOR CHANGING THE ORDER of materials !!!

This is due to decreased coupling between wall "leaves", because of a longer, softer air path.

Simplified - the best soundproof construction, regardless of WHICH materials are used, is TWO masses separated by only ONE air cavity. The larger the air cavity, the more reduction - the more MASS per leaf, the more reduction. Different acoustical properties in one of the leaves will also decrease sound transmission, because if both leaves have the same resonant frequencies, that frequency will pass through the wall easier.

All this is assuming you use enough of the right kind of caulk.

Anyway, first things first - hit the Radio Shack, get the meter (do NOT get the digital version, I haven't tested that one yet so can't tell you how good it is - and most digital meters don't have very good peak reading ability without a lot of practice)

Then, when you have actual SPL readings at the property line we can see how much more is needed, short of a bucket of water (hellllppp, I'm M-E-L-T-I-N-G...)

Oh, and I really WAS kidding about the "special" - tempted, but kidding... Steve

[liqdchris]

Thanks for the help. We do have a sound level meter. I was going to set up shop in the garage, measure the inside level, then measure the outside level. When I get those numbers I'll let you know.

Thanks,

[dennisfootpole]

I think when using a Radioshack DB meter you actually hold the meter perpendicular to the sound source, with your arm extended away from your body to avoid reflections (not pointed at the sound source).

>>>>
My boss read an exhaustive test of battery brands which rated Radioshack 9 volters above Duracell and Energizer, so he makes me use them for RF mic transmitters.

Good luck with the garage!

[knightfly]

The direction you point the RS meter makes very little difference in my experience - the mic element is about as omni-directional as you can get. The body "shading" the sound source would make a slight difference, possibly moreso outside, since there are less walls to reflect the sound and compensate for any "shading". Holding the meter the way you suggest DOES make it easier to read, though...

My only experience with Radio Shack batteries was with the crap they used to give you when you belonged to their little "battery-of-the-month" club - they weren't even good for paper weights. You can really get a wide range of quality in batteries - our shop clerk tried to save some $ on all the 9-volters we use, and there were only about 15% of those cheapo batteries that read more than 6 volts with NO LOAD other than the hi-Z DMM we were using to measure with - the whole batch got sent back, and we went back to brand-names... Steve

[liqdchris]

I have the digital DB meter form RadioShack. I have a Duracell Ultra 9volt battery in it.

I didn't have the manual for the meter so I went to RadioShack.com and found one there. It had directions on how to use it. I will be taking readings this weekend and posting my findings as soon as I can. Pretty much just stand in different spots around the outside while taking readings and report them from the different spots aye?

[knightfly]

Pretty much - remember to use the settings I gave earlier - have your drummer/bass man lay down a solid groove, check the levels IN THE ROOM first, at 2-3 different spots along the "evil neighbor wall", then while they're still playing go outside and check along the property line, if you see changes then record the high/low dB readings (peaks) at the best/worst spots.

This will give you both the effective reduction of the existing wall AND whether you are over the (usually) 50 dB at the property line number... Steve

[liqdchris]

I plugged in a minidisk player to a large PA in the garage. I blasted Stone Temple Pilots first album and turned the bass up a little. I got readings of 104-108 inside the garage.

I went outside and got high readings of 79-84 from the dryer vent and the edge of the garage door.

On the property line i was getting readings of 60-65.


I was thinking of at least having my drummer hit his snare along with it. Over all, you can still hear music inside there. If I add one more layer of walls not touching the existing ones similar to the layout I mentioned above, would that work?

The walls are all taped drywall now. I took the readings just before I sealed a couple more little holes. I was planing on building walls with metal studs, RC channel, some form of insullation (rockwool/r19), then 5/8drywall, and perhaps a layer of 1/2drywall on that. If I had the money, I'd get some soundBlock lead type sheet in between those layers.

Would that help bring the sound down much if I built a room within the garage like that? My main concern would then be the ceiling.

[liqdchris]

With those DB readings I got be ok with just playing music through the PA, or would I need to have my drummer/bassist play instead. I did have the PA up loud, really loud.

[knightfly]

As far as more wall construction, before you do anything more please go here

http://www.homer.com.au/phpBB2/viewtopic.php?t=86

and specifically check John's chart posted on Mar 01, along with my comments on Mar 17. Summation: MORE walls don't improve sound proofing, BETTER designed ones do. If you look at the chart, you'll see that in some cases you can actually IMPROVE wall performance by REMOVING material. This is what I mean by DESIGN.

As far as whether the minidisk thru PA thing is close enough to reality, it probably is. If you cranked the bass and were at 108, you were louder than the law allows at clubs (not that they obey it) - if it sounds like "live" in the room, you probably have a bottom-heavy enough "test signal" to get close. Remember, the bass is what comes thru the most.

The other thing that will make or break your efforts is TOTAL HERMETIC SEALING, inside and out. Anything less won't do... Steve

[liqdchris]

I've been looking around for insulation. I was thinking of using metal stud walls 16oc with 3 5/8 studs. What is the best type of insulation to use.

Owens Corning makes sound atenuation batts. They are like R-11 , same material as R-13. Would rock wool be better? Does it make a difference to have insulation that is more firm? If not, I'd be able to get the sound attenuation stuff and call it a day. There's also 703 board or similar stuff from Johns Mansville. Would that be better for isolation than the sound attenuation batts? Probably more costly for that though.

[knightfly]

Chris, I know how much you are probably hating the idea of ripping out stuff that's already there, but here's the unvarnished truth - YOU CAN'T GET THERE FROM HERE !!!

Please go back in this thread and follow the links I posted about wall designs. Each time you add more layers and more air spaces, you just spend more money making things WORSE while eating away even more of your usable floor space. The point I was trying to make in my post on May 8 is that you can actually IMPROVE some walls by REMOVING material. Check it out.

As far as the Sound Attenuation Batts, they seem like they would work well inside walls, similar to Rockwool - although I've not tried them, so I can't say for sure.

Metal studs are fine for wall construction, although it gets kind of tricky to use them for load-bearing walls.

The highest performance wall you can build for reasonable cost would be one with multiple layers of high density board, such as sheet rock and particle board, separated by as much air space as you can allow, with at least 3-4 inches of 3 lb cu ft rockwool or equivalent. Higher than 3 lb cu ft will help bass Transmission Loss some, but at the expense of highs. Lower than 3 lb cu ft density in the wall will do the opposite.

As near as I can tell from your earlier description, both your North wall and your garage door are now "Triple leaf construction" - This is a total waste of time, materials, and money, not to mention space.

If you're SERIOUS about making your space soundproof, you need to bite the bullet and TAKE OUT the extra construction, clear back to just the outer stucco and stud frame.

Be careful taking out the sheet rock, because you can re-use it, glued tightly to the inside of the stucco layer between the studs.

Put at least two layers of sheet rock against the stucco, glued in place and caulked. Then put up either rockwool or those SAFB's you found at the OC site, build an inner wall frame on rubber with 2-3" of space between the inner frame and the outer one (no paneling yet) - finally, if the inner frame is wood studs get some Resilient Channel and put it on the studs horizontally (check out USG's site on this, there are special ways to use RC)

If the inner frame is steel studs, the RC is optional and will only make about 2-3 dB difference instead of 8-9 dB. Every step of the way, caulk everything thoroughly with the best grade of Silicon or Butyl caulk you can find.

The end result should be only TWO centers of mass, the outside wall and the inside of the inner wall. The wider the separation between these two leaves, the better the sound performance. The heavier these two layers, the better the performance. Wherever possible, use fire retardant or fire proof materials, and remember that no matter what materials you use, if it won't float it won't stop sound. Seal EVERYTHING in TWO places, then you know it's sealed.

Odds are, your ceiling is one of the weak links - most attic spaces are ventilated, so the soundboard/drywall layer is your only barrier between inside and outside. If this is so, you need to figure out a way of getting two (sealed) leaves with air space in the ceiling, putting 3-4" of heavy insulation such as Rockwool or SAFB's between the leaves.

If those 2x4's you mentioned as ceiling joists are part of trusses for the roof, they will be strong enough that you could hang 2x6's under the existing ceiling, add Resilient Channel, then two more layers of 5/8 firecode sheet rock. That's assuming you have enough headroom - if not, you'd need to build UP instead of DOWN, which can get more tricky.

I understand the probable degree of anquish all my comments may have caused, but I didn't invent acoustical physics - I do, however, feel your pain and if there were an easier way to accomplish good sound proofing I would certainly tell you - all I can say is that adding even more construction will only end up making you even more frustrated. In the long run, backing up will get you farther forward... Steve