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Discussion Starter · #1 ·
Greetings I have a couple of questions that I just can't seem to find definite answers to so i thought i'd ask you guys.

1. Does anyone know the STC rating of a typical lowes 6inch hollow glass block window?

2. How would i go about sound proofing that as i am covering it up with my wall.

3. On another semi topic, I was reading about Genie Clips and was wondering if i have to install resilient channel/furring studs or anything like or can i just attach the clips to the ceiling joists? I was planning on using 5/8 drywall on the genie clips, sound foam, and possibly tape for the joists, what do you think, i don't want my movie watching to annoy anyone upstairs and i don't want to hear them in my man cave either hehe.
 

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the only real way to do it. is to build a room INSIDE of that room = the framing of the new room does not touch the rest of the house in any way. except, of course, where it sits on the isolation blocks that are set on the floor. anything else is going to let at least some sound through.
 

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I don't know the answers to your questions directly, but I can tell you what I'm familiar with. To isolate the window, I've seen lots of people put a covering over the window that looks respectable from the outside. Then frame a "plug" and fill it with fiberglass insulation.

Turns out, regular pink fluffy insulation is very good for sound attenuation. Much better than spray foam or rigid insulation because it does not couple the framing members which increases sound transmission. Unfortunately, fiberglass insulation can cause issues in a basement if installed properly. (I'm here with questions about that very thing).

I'm not familiar with genie clips, but I've read quite a bit about NOT using resilient channel for sound isolation. The problem is the specs are not standardized from one manufacturer to another. Part of the effectiveness of the decoupled system is achieved through flex in the system, and we dont have any data on the resilient channels out there in soundproofing systems. The systems I'm familiar with will use something like an IB1 clip and 25 ga hat channel with a hemmed edge to decouple from the framing. Then use lots of mass from something like two layers of 5/8" drywall with a damping material like Green Glue between them (not actually a glue).

Finally, I don't think treating just the ceiling will get the results you are hoping for. The issue is flanking noise into your walls. The sound transmitted into the walls will conduct up into the ceiling joists where it will travel into the floor and rooms above. HVAC ducts are also a major concern.

You might consider giving the guys at The Soundproofing Company a call. They are extremely helpful with soundproofing strategies and their website is full of detailed information on soundproofing strategies.
 

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The massive wall and damping is intended to provide the majority of the low frequency energy attenuation. Decoupling with clips and channel limits the energy transferred to the framing. IIRC the insulation's primary purpose is to prevent a resonant cavity, but will also attenuate higher frequency sound that slips through any holes in the room.
 

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I don't know the answers to your questions directly, but I can tell you what I'm familiar with. To isolate the window, I've seen lots of people put a covering over the window that looks respectable from the outside. Then frame a "plug" and fill it with fiberglass insulation.

Turns out, regular pink fluffy insulation is very good for sound attenuation. Much better than spray foam or rigid insulation because it does not couple the framing members which increases sound transmission. Unfortunately, fiberglass insulation can cause issues in a basement if installed properly. (I'm here with questions about that very thing).

I'm not familiar with genie clips, but I've read quite a bit about NOT using resilient channel for sound isolation. The problem is the specs are not standardized from one manufacturer to another. Part of the effectiveness of the decoupled system is achieved through flex in the system, and we dont have any data on the resilient channels out there in soundproofing systems. The systems I'm familiar with will use something like an IB1 clip and 25 ga hat channel with a hemmed edge to decouple from the framing. Then use lots of mass from something like two layers of 5/8" drywall with a damping material like Green Glue between them (not actually a glue).

Finally, I don't think treating just the ceiling will get the results you are hoping for. The issue is flanking noise into your walls. The sound transmitted into the walls will conduct up into the ceiling joists where it will travel into the floor and rooms above. HVAC ducts are also a major concern.

You might consider giving the guys at The Soundproofing Company a call. They are extremely helpful with soundproofing strategies and their website is full of detailed information on soundproofing strategies.

fibreglass does next to nothing, roxul is the cheap choice. spray foam goes way above that. its the material of choice on high end buildings where the owner actually cares about putting up a quality building.. guys that just throw things together use fibreglass
 

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fibreglass does next to nothing, roxul is the cheap choice. spray foam goes way above that. its the material of choice on high end buildings where the owner actually cares about putting up a quality building.. guys that just throw things together use fibreglass
Spray foam is a great thermal insulator, but I'm not convinced that it is the material of choice for sound isolation. Since spray foam is not massive, the sound reduction would need to be absorptive. However, closed cell foam does not allow the air to pass through, and will therefore be limited in its ability to absorb sound. Open cell would be better in that regard, but still would not seem to be as good as something like batt insulation.

To verify that, I went looking for hard numbers. Finding independent STC data on spray foam is difficult, but from what I can find it looks like an STC of 39 for open cell foam and less for closed cell foam (Icynene lists their STC as 37 for what it's worth). A common number for a wall filled with fiberglass batts is an STC of 39 as well. From those numbers it would appear that you would be paying a premium for the same performance (acoustically speaking) if you used foam. Further, you wouldn't use the foam in the interior walls if for no other reason than cost. Also, I don't think open cell foam is recommended below grade, is it? Another item to consider is foam rigidly couples the framing members together which becomes more of an issue at lower frequencies.

Finally, most of the high end theater builds that I have followed over the years have used fiberglass batts for sound control. These are professional builds, by some of the best in the industry, and in many cases the cost was of no concern. Granted, by follow I mean I looked at the pictures and followed the discussion online :)

I completely agree that spray foam is the material of choice for thermally insulating your home. But building a purpose build man-cave with sound control in mind may require some different materials since the objectives are different.

At any rate, I would recommend the OP contact a company that specializes in sound control, and research the topic thoroughly before moving forward. I've used The Soundproofing Company, and I've been happy with their customer service. I hope the OP is successful with their project.
 

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Discussion Starter · #10 ·
Well after a hard thought out process I decided on Hardieboard cement board, GG, 5/8" DW, GG, 5/8" DW. I was originally going to take the xps baord over the window but with only 3/4" cavity between that and the actually glass it was not enough room to work. So I decided to frame cut the xps board giving me any additional 2" to work with for a proper plug. I chose that specific cement board because it has no gypsum in it and is tested and rated for moisture and mold which was vital in case condensation showed up on the glass. It will also be sealed with acoustical sealant as well. Hope this helps and it made sense.
 

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Mass = best sound proofing. Thus use varied foams of insulation, drywall, glue, dead space, contact points, and surface. Then Seal it all.

The best soundproof room I've ever seen used this method top and bottom. Concrete floor had rubber gym mats laid over it, then insulation boards, then OBS subfloor, then rubber supports that the floor framing rested on. The floor frames where 2x4s going North and South then the dead space was filled with sand. OBS installed then 1 layer of cork, two layers of undermat, then then thick carpet. The walls where double walls with a dead air space between. SO 2x6 exterior wall spray foamed and Quiet Rock on the outside Drywall on the inside. 2" dead space. Then 2x4 wall with drywall facing the dead space, Roxul inside, then double layer of drywall joined with green glue, with quiet rock as the interior room piece. The ceiling had 2x10 joists which was sprayed with 2" closed foam, layers of drywall installed inside the 24" joists, then roxul then the bottom of the joists were with quiet rock. Then a 4" dead space, then Double layer drywall with green glue on 2x4 ceiling framing with roxul then double drywall with green glue and quiet rock as the interior piece. The ceiling of the room rested on the inside walls. The doors were double special order High end STC doors costing about $4k a PIECE!! Then ceiling and walls where covered with line carpet...like the stuff out of cars. Additionally heavy drapes were installed around the room. I was talking to the guy who did the install and he said he spent about $18 in materials for this room but I was silent on the outside with 120+dbs on the inside. Now would I do this NEVER because it's overboard but using Roxul, QuietRock, and Green glue is a good idea.
 
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