Anyone have suggestions for sound deadening interior finishes?

Oonrahnjay · May 06, 2012, 01:15:42 PM

Quote from: belfert on May 06, 2012, 12:55:49 PM(snip) Wouldn't Ozite be just as likely to get dirty as carpet? (snip)

Brian, I'm not really deep into soundproofing yet but I had had a little experience with Ozite. It's kind of a matter of degrees (in my experience) - Ozite is a lot better than carpet for avoiding showing surface dirt, catching dust, standing up to wear, etc. than carpet but it's much closer to carpet than say, a vinyl-upholstered surface.

Gerry H · May 07, 2012, 06:10:14 AM

Brian:
Sound is composed of many frequencies, both high and low. Most of the materials being talked about will attenuate high frequencies while doing little to the low frequencies. So identifying what type of noise you wish to control will help with choosing the best approach.
Insulation will attenuate high frequencies, the more the better for sound transfer and heat loss. Sometimes just adding furniture, items or "bodies" will knock down noise. Low frequencies are more about vibration and stopping the transfer there of.
I built a recording studio with floated walls and every trick I could find in the sound designers hand book, but underplayed the importance of the ventilation system supply and return ducts being a giant "hole in the walls" connecting everything, so little things can defeat all the greater work and money spent.
Good Luck Gerry H

jbnewman · May 08, 2012, 01:26:03 PM

In a previous home renovation, I used Green Glue to PVC water pipe noise (which happens to be a noise I hate), as well as to attempt to reduce general bathroom sounds. It did an exceptional job with the water pipe noise, and very well with voices. It didn't do as well with certain other bathroom sounds I hoped to reduce. It was probably worth doing, though.

DMoedave · May 08, 2012, 06:06:45 PM

Bruce, not sure of the exact thickness maybe 1/16th. It was shower pan material and i got it from an old plumbing supply that had some rolls with damaged edges at a decent price( most guys use the vinyl pans now). I have heard you can get it at roofing supplys as well.

belfert · May 08, 2012, 06:18:18 PM

If you know anyone who installs medical imaging equipment they sometimes can get scrap lead sheet from demolition of old imaging rooms, or scrap from new installs. The guy I know in that business lives 500 miles away so it really doesn't help me.

When installing lead sheet should you put screws or fasteners through it? I always thought fasteners transmit sounds, but I don't know how else you secure whatever covers the lead.

Lin · May 08, 2012, 06:38:24 PM

Would some sort of acoustic paint or coating work for the time being? It would be easy to clean and disrupt the reflection of sound. You can also add removable wall hangings that, although do not cover the walls entirely will break up sound wave reflection. Further, you can tell your friend to stop shouting.

belfert · May 08, 2012, 06:55:22 PM

I found some sort of paintable wallpaper that absorbs sound, but I have no idea where to buy it. It is a commercial product and only sold wholesale from what I can find so far. It is about 1/8" thick.

I'm thinking about several options. I need to find a place that sells Ozite locally so I can take a look at it.

Jeremy · May 09, 2012, 01:41:33 AM

Quote from: belfert on May 08, 2012, 06:18:18 PM
If you know anyone who installs medical imaging equipment they sometimes can get scrap lead sheet from demolition of old imaging rooms, or scrap from new installs. The guy I know in that business lives 500 miles away so it really doesn't help me.

When installing lead sheet should you put screws or fasteners through it? I always thought fasteners transmit sounds, but I don't know how else you secure whatever covers the lead.

Lead sheet is easily available from builders merchants and the like, but I don't think you would just buy raw lead sheet and attach it to your bus floor; there are all sorts of ready made sound-proofing materials which incorporate layers of lead (or lead substitute) material sandwiched between other materials. Depending on the application you would buy sheets of plywood with lead incorporated into it, or lead sandwiched between layers of foam.

The purpose of using lead is simply that it is a heavy, dense material which takes a lot of energy to make it vibrate - hence it tends to absorb low frequency sounds. If it is sandwiched between layers of foam, any vibrating it does do is isolated and not passed on into the room. The foam is also effective at absorbing the higher-frequency sounds, which get reflected around inside the foam structure.

I have some acoustic material which was spare after fitting out the engine room of a boat, and it is a 5-layer sandwich consisting of two layers of 'lead' and three layers of foam - except the lead isn't actually lead but some very dense vinyl-type material. Here's a couple of photos taken off the web of proprietary wood/foam/lead sandwich products:-

Incidentally, I don't think using mechanical fasteners can cause any kind of problem; they might transmit some sound, but very little given their tiny area.

Jeremy

Gerry H · May 09, 2012, 05:11:40 AM

Fasteners can definitely defeat the money spent on exotic materials. Anything that aids in the transfer of vibrations should be minimized or avoided. Try an adhesive of some type.
Those sandwhich type isolators are sometimes used on large machining centers and bolted to concrete floors with rubber encased lag bolts. The rubber isolates or impedes the vibration so the bolt doesn't "carry" it through to the floor.

Jeremy · May 09, 2012, 05:57:19 AM

That's true, and I've got my generator mounted on exactly that kind of isoelastic mount - but I don't think you'd try to use them to try to isolate the entire wall or floor panels in a bus.

Certainly use adhesive rather than mechanical fastenings - but I'm not sure that adhesive can be said to have any kind of 'anti vibration' properties, unless perhaps you're gluing the panels down with thick beads of silicone for instance, which might go some which replicates the rubber in an isoelastic mount

Jeremy

Tim Strommen · May 09, 2012, 09:01:41 PM

Used to do home theaters, so I've used these before, but I'm not associated with them at all...

Glue: http://www.quietrock.com/soundproof-products/damping-glue.html

The guys at "Serious Energy" make a bunch of products you might want to take a look at - sheetrock with damping material embedded, plywood with damping material embedded, acoustic sealants and glues (as linked above). They even have non-gypsum shetrock (no mold/rot).

Think of the planar surfaces as a diaphram, or the surface of a drum. You want to absorb vibration (lower frequencies), and difuse rather than reflect sound that isn't transmitted (higher frequencies). If you have space mineral fiber or "rockwool" in the wall will break up any high frequncies hat get past your first surface. A flat smoth face is likely to reflect higher frequency sound back in to the bus, so something with a textured surface (even like a beaded wood face) will help.

-T

Rts parts · May 10, 2012, 02:54:17 AM

I have used Ozite in several bus conversions with good results. As others have said before, heavy dense materials are the base to stop sound from being transmitted into the bus but Ozite is a great product for the wall and ceiling to attenuate the higer frequencys that bounce around. We typically cover the walls and ceiling with that thin bubble insulation with the aluminum foil on each side called reflectex or something like that. It has been a while but I think we got the last from Home Depot. It adds a small amount of insulation but mainly evens out the seams in the plywood joints so they don't show through the Ozite. Ozite is now owned by the Foss Company, they are great to deal with and will send you samples for colors and various textures. http://www.ozite.com/cprod.cfm?item=cp7

I havent bought any in a few years, but the largest roll they sell is about 6' wide and takes two men to carry it but is enough to do the entire ceiling and walls in a 40' bus. Thin contact cement down and spray the glue on with a cheap quart paint gun then throw the gun away. Very quick and easy.

Jeremy · May 10, 2012, 03:05:00 AM

Quote from: Tim Strommen on May 09, 2012, 09:01:41 PM
Glue: http://www.quietrock.com/soundproof-products/damping-glue.html

Interesting...I didn't know there was such a thing as 'acoustic glue' but it turns out that it works just as I guessed - applied with a gun as a thick (3/8") bead of rubbery material between the panels. Interestingly the instructions insist multiple times that the glue is not a 'structural adhesive', and that mechanical fastenings are also needed.

Jeremy

Ericbsc · May 10, 2012, 03:05:37 PM

Cheapest most efficient under the floor is mass loaded vinyl I think. I buy it in 48-96 wide roll. 1/8" thick. Roll out between floors. On the walls upholstrey foam with cloth, or vinyl works great. Just my 2 cents!!

belfert · May 10, 2012, 05:23:17 PM

Quote from: Ericbsc on May 10, 2012, 03:05:37 PM
Cheapest most efficient under the floor is mass loaded vinyl I think. I buy it in 48-96 wide roll. 1/8" thick. Roll out between floors. On the walls upholstrey foam with cloth, or vinyl works great. Just my 2 cents!!

Florr is already finished so that isn't changing. Does the vinyl really absorb sound? My thoughts right now are oak wainscot on the bottom and some Ozite carpet on the walls above that.