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Building a stereo room and ran into some problems, help!

I am in the process of building a dedicated sound room and have a couple of situations that have arisen that I cant find a suitable solution to (within threads of through google searches) so I am seeking advice here... background details:
1. Of course I want absolutely 0 sound transfer but I realize that isn’t possible as I haven’t won powerball as of this typing.. So, my goal is to let as little sound out of the room as possible (particularly bass) so as not to bother my wife and kids (that are either one floor above during waking hours or two floors above late night) or the neighbors whose walls are about 20-25 feet away... on a tight budget of course... Obviously I also want qualty sound inside but first things first...

2. The room is in the basement and I went with the "room-within-a-room" motif as the walls are about 3-6 inches from the actual walls, the ceiling is about 18 inches or so below the subfloor above. There is a crawl space below the basement floor so the floor is plywood, not concrete. The room is 11x15 with a 7 foot ceiling (low, but there’s a lot of duct work and piping so it was easier this way..)

3. Sound proofing/isolation: I floated the framing on top of some styrofoam I saw while buying the lumber.. From what I have read styrofoam isn’t the best sound proofing material but having something between the 2x4s and the actual floor sounded logical so I went for it in an effort to keep the crawl space from acting like a giant drum... At worst, I took a chance and blew 15 bucks... There are concrete walls surrounding about 1/2 the room and they are insulated, the rest of the interior area is pretty much open (walkout basement so the front 1/2 is underground sloping down so the back 1/2 is above ground..). There will be insulation between the studs (R13 I believe) and two layers of higher R rating (attic level stuff if memory serves...) in a crossing pattern between the "ceiling" of the room and the subfloor of the floor above. The walls will be 2x drywall with green glue in between the layers with regular drywall on the backside (outside of the room facing the rest of the basement.) Obviously will be sealing the gaps between the sheets of drywall, between the drywall and floor, around outlets, etc... Two cases of green glue have already been purchased...

3. On the table... as with most construction budgets, what you think it will cost and what it actually costs are two completely different things... So just like everyone else, money exists but supplies are diminishing.... I’m looking for effective and as affordable as possible...

The questions:
1. I am considering using the aforementioned styrofoam as a buffer between the studs and drywall.. adding the styrofoam means three layers of "wall" (styrofoam, drywall, green glue, drywall) on the room side of the studs. Thoughts?

2. I don’t plan on finishing the drywall so am curious about how to "finish" the walls and have the makings of a good sound space and also contain sound as much as possible...this is a dedicated room so functionality is the important part... My original intent was to put industrial carpet on the walls and call it good (then add panels as necessary)... I am also considering curtains or large panels that are similar to moving blankets but made specifically for the purpose of absorbing sound... The curtains I am seeing are marketed as black out curtains but the sound isolation benefits are mentioned.. and it’s relatively cheap... I doubt their sound absorption capabilities are "all that" but it is an option... Thoughts or other recommendations?

3. The ceiling... In theory I was/am going to do the 2 layers of drywall and green glue here as well... Ran into logistics as that gets REALLY heavy really fast... So, out went the 2x4s and in came the 2x6s... So now that I have the capability; considering I already have (from high to low) subfloor above, about six inches of open air between the joists, the two thick layers of insulation, and at least 1 layer of drywall.. is the double drywall and green glue necessary?
3a. All of the web sites have begun to blur together but I believe I saw information that stated 2x6s can hold the weight of the two layers of drywall

4. I need to get air in and out of the room, without negating all the aforementioned efforts.... I am blocking off the air vent (physically stuffing the vent with a blanket and not connecting it to the room at all as it is above the ceiling) that would go to the room in an effort to not funnel sound directly to the rest of the house.... So far, I have come up with something along the lines of flexible tubing (dryer vents?) with baffling similar to a muffler inside to simply circulate the air from the basement in and the room air out... this isn’t even an educated guess as I have no background knowledge whatsoever... obviously any thoughts on this would be greatly appreciated as I have found no information anywhere on this issue...

5. The drywall itself... Pretty much everything I have read has stated that 5/8 drywall is far superior to 1/2 inch and one would be a fool not to use it... However, the research presented on the green glue website pretty much contradicts this as the thickness of the drywall had no impact in the final rating (I believe the acronym is SRA). Thoughts?

Any thoughts on on these ideas would be greatly appreciated!!! Also open to suggestions as well but at this point cost is becoming more and more of a factor as I am pretty much already 2x the intended budget so please keep that in mind...

thanks!
la10slgr
ivan_nosnibor's avatar
ivan_nosnibor
1,047 posts
 
If I’m reading #4 correctly, stuffing any kind of blanket or such into the inside of an air vent as a longterm solution would be a big fat no-no. There will be far too much moisture buildup inside the vent system during normal use and it won’t be long before you can have a serious mold problem on your hands that will require professional remediation that would likely not be cheap.

The best ducting from a noise transmission pov, that is, noise transmission along the length of the duct itself, is the foil kind. They are cheap and quiet, a bit delicate maybe, but if anything happens to it, it can be replaced easily enough...much quieter than the sheet metal, boxed ducting which would require all kinds of noise insulation on the outside of the ducts and they still might not be as quiet as the foil type. But, that only concerns noise transmission along the duct material itself, not along the airway inside it. For that, I’m not really aware of a workable solution unless you’re able to reroute your ducting to a degree and can exit your room air to another area of the house least bothered by the noise, either straight to the HVAC return, or, if there is sufficient return airflow from it, to another room.
juancgenao
64 posts
 
Go to Home Depot, and get ROXUL, insulation , to install between 
the studs, great product, and not too expensive, just finished my room, about six month ago, and is a garage convert, dead quiet,
my wife don't even know when lm in the room playing music,
have a concrete floor, that helps, but very happy with my decision,
to use roxul instead of regular insulation,also used 5/8 Sheetrock boards,
good luck:
regards:
la10slgr OP
44 posts
 
Randy
the walls are 2x4 and are already built so that part is what it is.  The 2x6s came in to play as joists for the ceiling of the room to make sure they are strong enough to support whatever ceiling solution I end up using..

The carpet I am looking at is that superthin industial carpet that you see in businesses and such with minimal pile (maybe 1/8 inch thick overall.)    The exact one I am considering is 50cents/square foot at Lowes so that should speak towards its overall thickness/durability as carpet...  Do you still think that might make it too dead?

I've looked at recording studio solutions but so far the general idea I got from most of that is since one is building a studio they must be pretty serious so spending a few grand on the walls is on the table...  I'm trying to take this seriously but not that seriously....  Admittedly I have avoided concert hall stuff as I didn't think it would apply enough...  Will continue to investigate...

As for the book, I just found some recommendations toward that end yesterday (but noooo, couldnt have found that within my past three months of snooping around the innerwebs.... 😡) unfortunately time is of the essence...  

gs5556
There was no room to begin with as the basement is unfinished.  I hope you are right when you say the room will trap more sound than I think but this is pretty much a one-shot deal (not absolute but you get the gist) so want to be as effective as possible the first go around... My goal is to be able to listen to the music as loud as I want (just shy of making myself go deaf) whenever I want without a complaint from my wife or neighbors..  I could very well have a nervous breakdown if I finish this project and the neighbors hear anything, bass included..  You wouldn't believe the number of hours I have spent trying to educate myself about sound isolation the past three months.. I knew next to nothing when I started this project...  not that I know anything now but my eyes dont glaze over like they used to when reading this stuff..   I would be more open to "playing" around with different ideas but changing things around once built is pretty cost prohibitive 

ivan
good point on the blanket to plug the existing duct..  you wouldn't believe the occupation of the person that suggested it but based on your comment that is definitely out!  Thanks for the save!!!  

As for the foil for the airflow, that's exactly what I was thinking so it seems I am on the right track..  The basement is cool year round so at this point I am not worried about getting a/c in (although we did frame an opening for one for future use if needed.. ounce of prevention, ton of cure!) and I think between the insulation and the heat from the electronics it will be warm enough so all I am worried about is getting fresh air in and circulating it through...  At this point, my intention is to have an opening near the front of the room to draw "fresh" air from the basement in and a small fan and opening at the back of the room to suck the air out and blow it into the basement...  Lot of comments I have read mention that the slightest air leaks (even from unsealed outlets) negate all the other sound proofing efforts so I am wanting to be careful here...  At this point I am looking at building some sort of an insulated box around the openings to mitigate sound escape but haven't come up with a solid plan as yet..

thanks for your comments and keep 'em coming!
la10slgr OP
44 posts
 
juancgenao
looked into roxul but bought regular insulation... cant remember exactly why but there was a reason (I bought the insulation a while ago to help spread out the cost of the project...)  At any rate, I already have rolls upon rolls of insulation sitting in the corner waiting to be used...  Hopefully I can match your sonic bliss with what I have.. thanks for the recommendation! 

As for the 5/8 drywall, like I said in my op, general consensus is definitely use it but the green glue research made me question the efficacy... not to mention the weight when hanging from the ceiling...
la10slgr OP
44 posts
 
Randy
just reread your post and noticed your recommendation for soundbreak.. will look into it.. I will say Im not a fan of websites that make you give information in order to access basic information such as test results (to get STC rating) and price....
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