SOUND-DEADENING BOARD

[nukmusic]

SOUND-DEADENING BOARD ??? good or waste of time. Didn't find any prices either.

[knightfly]

'pends on who's calling what a "sound deadening board" , and where you wanna put it - got any more details, maybe a link? Steve

[nukmusic]

it's said to be lightweight, which would be real easy to handle. I'm still searching for the cost per 4 x 8 sheet. STC looks about the same as adding a resillient channel???

Sound board is a material made from compressed wood fibers (Sometimes called "construction panel") another similar trade name is "Homasote" ( Somewhat better, but considerably more expensive) and it functions as a thick paper cushion.

http://www.fiberboard.org/sound_pubs.html

http://www.fiberboard.org/sources.html

Rockwool vs Cellulose????
http://www.comfortech.biz/stc_info.html

also something to pass on :

It is important to distinguish acoustically effective resilient channels from hat channels, z-channels, and other lightweight metal furring systems that drywall contractors are used to installing. These other systems may resemble resilient channels, but they allow no movement and are simply too rigid to be effective. Only true resilient channels have any acoustical benefit.

[nukmusic]

now I'm lost............

Sound Board (fiberboard): Sound deadening fiberboard manufactured specifically for use in sound rated wall partition and floor/ceiling construction. When product installed with two ½" drywall sheets, they shall have a minimum Sound Transmission Classification of STC-46 or greater.

Drywall, 5/8" x 4' x 8' $6.88

Sound Board (Wood Fiber Board), 1/2" x 4' x 8' $7.68

[giles117]

What you have posted is similar to celotex. On a wall The it is recommended 2 - 5/8" Sheest of drywall and the fibreboard sandwiched between them.

Cellulose is denser, yes, but rockwool is MUCH easier to handle and the few db in difference will be negligible compared to the amount of work required to install the materials.

Bryan Giles

[knightfly]

OK, J, what you were looking at really IS sound board, as it's referred to normally - you never know, we get some strange materials brought up once in a while.

Now, what's confusing you - specifically, what are you trying to do (and where) with the sound board? As Bryan brought up, the normal construction would be two layers of 5/8 sheet rock with a layer of Celotex/Homosote/Sound board between them. This gives a SLIGHT decoupling effect, but the main reason it works is that the sound now has to change "mediums" from air to sheet rock to Homosote to sheet rock to insulation/air, then repeat on the other side of the frame, to get through. Since sound loses some energy every time it changes direction (diffraction) and speed (different material) the net result is more Transmission Loss.

Yeah, I try to mention once in a while about the different kinds of channel but maybe you missed it - there are special isolators available for the hat type channels, but if you can find RC-1 it's usually more reasonable cost-wise than going that route.

Here's a link to hat channel isolators -

http://www.acousticalsolutions.com/prod ... /clips.asp

But, at $5 a pop if you're using wood studs on 24" centers, a 12 foot wall section 8 feet high with 2/3 layers on channel would cost about $100, just for the isolators!!! Then you have the cost of the hat channel on top of that.

BTW, their recommendation for spacing of the resilient clips is 24" centers on top and bottom rows, then staggered on 48" centers thru the rest of the wall. Otherwise, if you stuck to 24" centers, the clips for an 8' x 12' section of wall would run about $240 just for clips.

Sorry, kinda digressed there - J, if you could state specifically what you're trying to do (and maybe how and why) it would be easier to tackle than random bits and pieces... Steve

[nukmusic]

Sorry....Just trying to finish the studio(20x20x10 garage) and please the wife at the same time. For her new house she "NEEDS " a new sofa set, patio set, curtains, fence, etc, etc. I'll never save enough for those $5001.03 speaker cables we talked about. But anyway......I was just looking at combining materials to beef up STC. I already have the interior walls up. They're 2x4 wood studs, 24"o.c., except the wall in front of the garage door which is 2x6,none are load-bearing. I used the existing outer walls(rear of live booth and right CR wall) and rear inner wall(rear of vocal booth and closet). Using a sound meter I tested the STC of the existing walls, standard contruction: brick>shreadboard>2x4 framing>5/8 drywall. I cranked up the speakers to 100db and on the other side of the wall the meter read 60db. I could just hear the kick and bass from the sidewalk(14ft away). My home is on the corner so I only have one close neighbor to "Not Disturb". If you remember, I changed the design to the one below which should work better for me in using existing walls, meaning..... I'm trying to use the washroom and master closet as a sort of sound lock with seems to work pretty good. My main concern is for a little more isolation with the existing outer walls(rear of live booth and right CR wall)and the ceiling. The ceiling/attic should be easy, it's 2x12 framing .

[knightfly]

OK, so what is already there, as far as the outer walls? Can you do a basic drawing of them, layer by layer, from the outer siding clear through to what you see from inside the studio, along with whatever text it takes to clarify?

From your tests, it sounds like you're already close.

Also, check out the ceiling construction pix on the SAE site again, to see if any of those will help... Steve

[nukmusic]

ok..I'll see if I can explain.
if you look at the 2 pics I have converted a standard 20x20 garage. The washroom and walkin closet will go untouched, which should work as a sort of sound lock between the studio and the rest of the house. I have only used the the 20 x 20 ' area inside of the garage.

north, east, and west existing walls are(gray in color):

Brick + 2" air gap + 7/16" shrandboard(plywood) + 2x4" wood framing(with standard insulation) + 1/2" drywall. Standard home contruction.

The north wall has the large 2 car garage door.
the south existing wall:

1/2" drywall + 2x4" wood framing(with standard insulation) + 1/2" drywall.

one side is garage and the other side is the washroom and walkin closet, then another standard wall.

all the new inner walls(black in color) are framed with 2x4" wood, and that's as far as my wife let me make it ***I have framed a 2x6 wood wall in front of the garage door (north wall)...... I wanted it to look like a garage from the outside of the house.

the existing ceiling:

1/2" drywall + 2x12" wood framing + attic(no insulation in attic over garage)

I mostly listenback with headphones in the control rm when recording vocals, so I was looking for a simple when to finish the inner walls. I may need to add something to the wall east wall in the live rm and the west wall in the Control rm to help with STC. My only close neighbor is to the right of the control rm

[knightfly]

OK, I think I've got the drift now -

First, the door(s) on the right are most likely going to be a weak spot unless you've already spend a few hundred on each one for custom seals and drop thresholds, something like this -

http://www.acousticalsolutions.com/prod ... l_kits.asp

The next weakness would be the standard construction - those brick walls need weep holes for moisture control, so the brick is almost not there acoustically. This means you have effectively a 2-leaf wall consisting of the Strandboard outside, the standard insulation, and the 1/2" sheet rock inside. If that wall were acoustically caulked, at least on the inside, you'd be lucky to have an STC of around 35. If you're losing 40 dB as is, count your blessings. Just adding more layers of sheet rock on the inside will probably frustrate you. With 5/8" rock, you might get 3-4 dB for the first additional layer, then 2-3 dB for the next - that amount of improvement might just be enough, but if it doesn't quite make it you're screwed. You can get about 9 dB improvement by doing the following:

I know you don't want to hear this, but the only way you're going to get much of an improvement in wall isolation is to REMOVE that inner layer of sheet rock, get Resilient Channel onto those studs, or if you had the room, put a completely separate steel stud frame inside with more insulation and at least two layers of sheet rock on the inner side of that frame.

With resilient channel on your existing frame (removing inner wallboard first) then adding two layers of 5/8" sheet rock, your walls should no longer be the weak link.

As for the ceiling, again the only way for serious improvement is to remove the existing wallboard and put RC up, adding a couple layers of 5/8" sheet rock over that.

You could just add a layer to what you've got, blow in cellulose insulation (10 inches if possible) and put sound board with plywood above it on the tops of the joists, but the problem here will be flanking noise. Each of those 2x12's is exposed to sound at the ends, tied into (probably) a fascia board which will transmit sound along the joists allowing it to radiate thru the solid connected sheet rock and into/out of your studio. You really need to break that path, and an inner leaf floated on RC is about the only practical way I know of.

One way to find out just how much more isolation you REALLY need, is to have a helper in the room to adjust the volume while you talk to them from outside with a cell phone and your SPL meter - have them turn down the volume til you are happy with the level outside, then measure it there, measure it inside, see how much louder you want to be able to have it inside, and that's how much improvement you need to achieve minimum.

If that difference is only 4-5 dB, I'd just put a couple layers of sheet rock on outer walls and ceilings, caulk well, and call it good... Steve

[nukmusic]

One way to find out just how much more isolation you REALLY need, is to have a helper in the room to adjust the volume while you talk to them from outside with a cell phone and your SPL meter - have them turn down the volume til you are happy with the level outside, then measure it there, measure it inside, see how much louder you want to be able to have it inside, and that's how much improvement you need

never thought about this, tried it! I need(want) about another 5db of noise redution. You're the man!

one more question.....with adding a few sheets of drywall.....

would a sandwich work better? meaning.... drywall + sound board + drywall (all glued together) or just different thicknesses of drywall?

Thanks.....I'm off tto home depot and lowes

P.S. very strange idea ....I was in a small studio earlier today that used 5/8" drywall + 1 1/2" styrofoam sheets on each side of 2x4 framing(with insulation). It really works. weird right? They got the styrofoam from a company that makes real large refrigirators.

[knightfly]

J, the sandwich would work better, any time you can "confuse" the sound it has a harder time getting through. Gypsum has a sound propagation speed of about 22,000 feet per second, solid fir is about 12,000, and air is 1130. Each time the sound has to change speeds, it also gets diffracted (bent) then bent back again to the original course but offset - going from air to gypsum to MDF or celotex to gypsum to insulated air, then thru the other half of the wall, takes a lot out of the sound (that's a GOOD thing)

For your walls, adding sheet rock/sound board/sheet rock should give you the 5-6 dB you need.

As for fastening, you shouldn't glue the new layers on because it will make them act as one panel. That can be ok in some ways, because it lowers the resonant frequency of the panel and makes it harder for lows to get through (as long as they aren't at the resonant frequency) - however, using screws to attach the separate panels lets each act at its own resonant frequency, which further blocks sound (it passes thru more easily at resonance) by making the wall have multiple resonant frequencies, so no ONE frequency finds an easy path through.

On the styrofoam thing - refrigerators use closed cell foam, which has very little acoustic use other than a slight attenuation. I think the main thing helping those walls out is the extra effective 3" of distance between leaves caused by those layers of foam under the wallboard.

I once did a (sloppy) test of a refrigerator to see if one could be used for a computer silencing box - I put a ghetto blaster in the frig, cranked it up to 90 dB on my SLM, then closed the door - it dropped by about 36 dB... The only thing that stopped me from following thru was that all the frig's I found were either too big or too small for my control room. It did tell me that magnetic seals work really well around doors, and then (just my luck) Stanley decided to discontinue their magnetic sealed prehung exterior doors in favor of a less effective one... (sigh)

Anyway, glad you only needed about 5 dB, that's certainly doable without major re-construction... Steve

[nukmusic]

Thanks Steve, You should see the smile on my face! Now I can use the extra cash on those $5001.03 cables. I'll take some photos along the way.
I know a friend of mine that used 3 layers of the black asphate sheating on metal studs(and no drywall) that worked. The stuff is like soft particle board, lightweight, and about $4 a sheet(4x8). But I think it's flamable.

[knightfly]

Don't even THINK of doing that - the 5/8" firecode sheetrock is only about $6 a sheet, more mass, and NOT flammable. Insurance doesn't make kids not miss their dad, assuming they survive the fire.

PLEASE READ MY ANNOUNCEMENT AT TOP OF THE FORUM... Steve

[lorrizzi]

Just out of curiosity, I'm new to this forum:
I didn't get how you shut the garage door, if it is just a wood frame partition it could be your weak spot, you should increase its mass as much as possible... masonry would be the best!

Cheers,

Lorenzo