i've heard green glue is over priced and can be replaced with thin(1/8") sheets of roofing material.

same idea
rubberish substance between layers of drywall/particle board helps slow the vibrations of the wall/ceiling.

the general idea in sound proofing is Mass/Air/Mass
one Mass absorbs by slowing the energy, then the air deadens that, then the next mass stops what didn't get threw.


the J/Z channel will also help the ceiling absorb more acoustic energy.

and if air can get threw it, sound can get threw it.
that said,
the problem with an airtight room of course is the ventilation.
especially when that room is filled with sweaty punkers.

that's not to say that you can't solve these problems on the cheap.

we've been dumpstering huge sheets of particle board from the furniture company down the road.

if you're in the states, you should be able to find a decent airconditioner second hand.

look for surplus building supplies.

Don't book Great White.

D'Piucchstre wrote:

scott wrote:
You should fill the space beteen the joists with fibreglass batt insulation, probably like R19 or so. Then hang two sheets of drywall on the underside of the joists. If you wanna get fancy with it, go for the floating ceiling thing by using that J-channel stuff. Make sure all your seals are airtight, where the ceiling meets the walls.

Rock Wool is the stuff that's usually used for sound deadening/soundproofing, whereas Fiberglass batting is usually just used for insulation.

I would respectfully disagree, after having used fibreglass batt insulation on a number of big fancy sound insulation projects, including the program at O'Hare airport where I used to work as an acoustical consultant on the noise abatement program. For absorbing sound, it's one of the best materials out there.

When you say "usually", what do you mean?

And as we all should know by now, the word "soundproof" is useless. The only place that's actually soundproof is the inside of a vaccum, where you would of course explode instantly. And nobody wants to be there.

I think rockwool and fiberglass have pretty similar acoustic properties, given the same density.

fucking different costs tho'

"Awesome! Good luck with filing an insurance claim after the catastrophic fire, now that you've publicly declared that you're filling this fake ceiling with flammable stuff. "


not so sure that the plywood ceiling is going to be that much of a fire problem, considering we are already a record book store and have such stacked all throughout the building. If our store catches fire we're fucked. same goes for any record/book store. for what its worth though I do spray the magazine/records that im sticking in the space between the ceiling and the upstairs floor with a boric acid /alum mixture which is a flame retardant, as well as a fungicide as well as keeps out vermin. . Something very similiar to what is used to treat commercial cellulose(cotton) insultaion. From what ive read elswhere regular fiberglass insulation does very little in regards to sound dampening. I'e seen a few results from independents labs that tested the ability of fiberglass insulation and it provided very little dampening. I'm using the treated magazines/old records to add mass, it may not be the best material, but its free. I'm going to experiment with some latex polymers and see what I can come up with that would work in hte same way as green glue. If I can get a formula thatss cures in the same way Ill apply it between some sheets drywall and see what happens.

I'm not looking to hire an acoustic consultant, its just a basement used for band practices and a few shows a month. Just wanted to see what I could do to dampen some of the sound as a courtesy to the neigbors. Everyone that lives in the building moved in after we opened the store and knew about the shows before hand so its not really that big of a deal.

This is a pretty good reference as well. The fiberglass does make some difference... The STC is really the figure of merit for what you are doing. Absorption values are really more relevant for the sound inside the room.

and something worth noting is that in a case like this, where what you're concerned with is the transmission of sound from one space to another (TL) one of the things people often think to do is put absorbative materials in the room where the band is, and this can be the exact wrong thing to do. you end up with a weird-sounding, unnatural space that's sucking up the mids and highs too much, and what ends up happening is the guitarist and bassist turn up their amps to compensate, which ends up producing more low-frequency sound which is the source of the transmission problems in the first place.

diffusion is often a good solution, but only if the band room has shitty reflection problems and really requires it. if you're going to treat the band room, diffusion on the side walls and bass traps in the corners is often the way to go. but without hearing the actual sound in the space, one can only guess.

ebeam wrote:This is a pretty good reference as well. The fiberglass does make some difference... The STC is really the figure of merit for what you are doing. Absorption values are really more relevant for the sound inside the room.

Does anybody have a link to what that number actually means? I'm going to be converting my detached garage to a practice/recording space and I'm looking for hard numbers. I'd really like attenuation as a function of frequency for a few different construction methods but have only found these same STC numbers.

Hey apop, I've "soundproofed" several rooms and acoustically treated quite a few as well. And I live in St. Louis, a block and a half north of Benton Park. And I've been in you, and bought records.
I'd be happy to help if you'd like.
You can PM me through this site or email me at danielruder AT gmail.