soundproofing (1 Viewer)

[Megan T]

Just to let you guys know this is a great site. I am in the process of building a Audio/HT/rec room. The room is aproximatly 350 square foot. My goal is to keep the noise contained downstairs with a limited budget. So far I had installed "quiet zone" fiberglass in the ceiling joist. I also came across some black roofing vapour barrier (it is like paper). Is this a waste of time? Will I notice any audio difference? Thanks

 

[Bobby C]

Hey Megan,

As to the black roofing vapour barrier - I'm not sure, I'd guess it's not going to be that useful but I'd be curious to what others say. The fiberglass will be useful (also good in the walls), especially for high frequencies. But the best thing you can do to contain sound is adding mass - the best source is drywall. Those that can afford it will install 2 layers of drywall. This, in conjunction with decoupling the room (through staggered studs and/or something like RSIC clips) seems to be the most favored method of containing sound. However it doesn't take long for a tight budget to get blown if you're going all out - good luck!

 

[Megan T]

Thank's for your input. I guess I'll start returning the unfinnish supplies. I also notice that if you are not using your fireplace cover the opening with a piece of plywood or sheetrock. This have greatly reduce sound.

 

[ScottATL]

So would it be better to put in thicker sheetrock, say go with the 5/8 vs the 3/8? Would this make much difference, it's quite a difference in the wallet.

My house is a 2 story with a basement, and all of our bedrooms are on in the upstairs with the main level just kitchen living room, office, ect. I'm only concerned about waking the kids up late at night. 3 of the 4 walls in the HT room are concrete too.

 

[Bobby C]

I'm no expert, but from everything I've read and heard, the more there is mass, the less there is sound leakage. So, all things being equal, yes, 5/8" would be better. That being said, however, you need to be concerned with other areas of leakage. Let's say, for example, you isolate the room with staggered studs and you double sheetrock using 5/8". This would be an excellent first step. But let's say that you don't have a decent door or your outlets are caulked, much of what was achieved would be lost.

 

[Wayne A. Pflughaupt]

For soundproofing on a budget, you can go along way paying attention to the basics. As noted, mass helps a lot. The best way to get it cheap is to go with double layers of 5/8” sheetrock. Internal insulation will help some, but not tremendously.

Keeping with the mass, any doors between the HT and other rooms should heavy solid core.

The other factor for soundproofing is an airtight room – once again, at least between the HT room and others. Therefore you want to stagger the seams of the double sheetrock, caulk the corners, outlet boxes, etc. The door should be completely weather stripped and have an airtight threshold.

A problem you get with an airtight room is that the air conditioner will not work right, because they typically rely on leakage around and under the door for the air return. Therefore you need to install an air return vent in the ceiling.

Regards,
Wayne A. Pflughaupt

 

[Bobby C]

Megan - listen to Wayne, he is the man!

 

[SteveCallas]

There are always a lot of threads about soundproofing, and I still think this stuff would work better than an extra layer of drywall or trying to add a lot more mass.
http://www.quietsolution.com/quietrock.html

I don't have any experience with it yet, but it sounds logical and can just be added over drywall.

 

[derek]

How bout soundproofing for the ceiling? An extra layer of sheetrock wouldn't seem practical. Is recessed lighting a concern? I plan on using fiberglass insulation in ceiling joists but am concerned with sound traveling up from my basement HT to the room above when things are cranked up. Right now I can hear the tv/stereo fairly well while in my unfinished basement from the room above where the equipement is located.

 

[Bobby C]

Derek,

I'm in the same boat as you - to me my biggest concern is noise traveling upwards. Like you say, even without things cranked up, sound bleeds easily upstairs.

I'm going to use (among other things) an extra layer of sheetrock in my ceiling. As it is, I have low ceilings, but the sound isolation benefits outweigh any height loss.

 

[derek]

What's the consensus on recessed ceiling lighting? Would those openings eliminate some of the benefits of double sheetrock/resilent channeling/insulation etc?

 

[Bobby C]

I would imagine that it is a source for sound loss. However if the cans are sealed with acoustic caulk, I'd imagine you'd lessen the loss.

 

[JasR]

You can buy special acoustic (also fireproof) recessed lighting. (We call them downlights in Aus.) Fairly expensive but do a great job.
I find that deep base is the major problem going upstairs through the floor. Would definitely recommend 2 layers of acoustic drywall (Soundcheck in Aus) with the special decoupling clips (mentioned by Bobby C) otherwise the sound just travels through the timber floor joists above.
In regards to the sound coming from upstairs as a guide, I have found that the sound coming down is greater than that going up, because the TV upstairs is in contact with the floor above, therefore a direct sound transfer. Where as the sound from downstairs is indirect and has to vibrate the air first which then inturn vibrates the floor above which is them reconverted back into sound waves.
Bob.

 

[Bobby C]

Wayne stated: "A problem you get with an airtight room is that the air conditioner will not work right, because they typically rely on leakage around and under the door for the air return. Therefore you need to install an air return vent in the ceiling."

Makes perfect sense, however if someone goes through all the trouble of a room w/in a room, double dryalls, uses acoustic caulk, etc., isn't this completely compromised by an air return duct? I imagine there are ways of minimizing sound loss through ducts (I'm curious to hear what they are), but still a hole is a hole.....

 

[Wayne A. Pflughaupt]

Perhaps some, but no more than what you'd get with the air inlet you already have.

Consider that the sound would have to travel some distance along a path full of bends and turns to the AC unit, where it is diffused by the coil and other hardware, then out from there in many directions to other rooms, again, with many bends along the way. Not much chance any appreciable noise will make it to the end of all that.

Bottom line, any loss with a return vent will be made up for many times over by the gain of an airtight room.

Regards,
Wayne A. Pflughaupt

 

[Bobby C]

Thanks for the reply. I actually need to bring air into the room as well. My main plenum is maybe 10' from the room (running parallel to it). I was thinking of running flexible (round) duct from the plenum into the room, inside a joist. If this is a desirable approach, does making the run twist & turn a bit a good thing?

 

[anth_c]

Bobby,

In order to reduce sound transmission, you would want to use ducting where the insulation is on the inside...in addition to providing thermal insulation, the internal insulation will absorb sound.

I've also recall some information about people making plenum boxes that act like a car muffler: it is basically a box that has an inlet and outlet with a baffle in bewteen, such that the air has to make a couple of 90 degree bends. The entire inside of the box is covered with sound absorbing materials.

I even think some of the hometheater sites offer ready built solutions, they call them duct silencers or something like that. I think there was an article in Home Theater Builder magazine where they had a DIY version.

Regards,
Anthony

 

[Bobby C]

Ahhh - sounds great. I'll check this out with a visit to my local HVAC supplier.

Thanks!
Bob

 

[Quiet Zone]

Quiet Zone Acoustic Insulation is awesome. I also used Quiet Zone to insulate my home theater. I used it in addition to Quiet Glue between two staggered thicknesses of 5/8" gypsum. Of course, none of this can go into place until every little crack is filled with foam and/or silicone! I have a ton of Quiet Zone Batts left over (enough for 3 home theatres- misordered and can't return). If you're in the market, let me know!

 

[movie fanatic]

The insulation of the HVAC system is a good point when it comes to soundproofing for the HT system. That, and it will make the sound from the HVAC system less annoying when you are trying to watch your movies! Is there a certain kind of soundproofing recommended for such a project?