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Old 07-27-2014, 12:01 AM - Thread Starter
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Sound Isolation again - confused about proper isolation for the theater

We're converting the garage into a home theater as part of our total house remodel. So #1 , cost is an issue due to all the cost overruns on the rest of the job. If it were up to me, I'd leave the garage as it is with open stud walls and do this part of the project later. But apparently we have to close it up to pass final inspection.

I've attached a copy of the layout of the home theater. I've read through a ton of stuff on this forum and on Sound Isolation Company's website. Yesterday I met with one of the drywall subs who's bidding the project. He didn't seem very flexible on how to sound isolate. His idea was to use the hat channels secured DIRECTLY onto the studs. No clips. Hmmmm. Then he said that the cost of doing double layer of 5/8" sheet rock with Green Glue was going to be higher than the cost of a single layer of Quiet Rock 500 with the acoustical sealant and putty pads. At least he knows about putty pads! He quoted about $100 per 4x8 sheet of Quiet Rock installed. We need about 40 sheets in this 21x19x9.5 room.

I plan on building a couple of 18" subs. I know sound isolation works really well for high frequency sound waves, but many have stated that low frequency long wave bass tends to go right through most stuff. For that heavy mass such as mass loaded vinyl is preferred. But that stuff is very expensive.

Some questions:

1) I just learned about another product - Homasote 440 which has an STC of 55. This stuff looks very promising, and it's less than 1/2 the cost of the Quiet Rock. Does anyone have experience with this stuff? http://www.homasote.com/Installation...highlights.pdf

It would go over the clips and channels and then a layer of sheet rock would go over on top of that. Has anyone had experience with this product?

2) The other issue is our media closet. Current plans are for a door to enter the media closet from the side of the theater. The biggest issue is the equipment rack is going to face the theater so that's a giant fenestration allowing sound to leak right through. We could sound isolate the media closet itself, but clips and channels will be very difficult to use in such a small space.

Would it be more practical to just turn the stand 90 degrees so that it can only be accessed by opening the closet door? Everything could run off an IR repeater. This way at least we have a good wall to isolate the sound and not have an fenestration for the rack.

3) Finally, the former garage door is going to be a solid wall, except I'd like a 36" door for ease of getting stuff into and out of the theater. I don't want to drag stuff (especially construction materials) through the rest of the house. I know heavy mass is better. MDF is preferred over foam. I plan on getting spring loaded bottom of door sealer, and perimeter sealer. I might even cut a piece or two of Homasote 440 and overlay it onto the door on the inside and then cover that with some acoustic cloth. So I'm looking for an exterior door, 36" x 6'8", that's best suited for sound isolation. Are there preferred doors for this kind of application?
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Old 07-27-2014, 03:29 AM
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you should be getting you advice from Ted at Soundproofingcompany.com. You will also save money.

forget about Homasote , you can't beat damped mass for isolating bass frequencies.

Two layers of 5/8 with Green Glue.
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Old 07-27-2014, 03:31 AM
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build the media closet after the theater shell is built, so the entire space is inside a soundproofed drywall bunker.
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Old 07-27-2014, 12:39 PM - Thread Starter
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Quote:
Originally Posted by BIGmouthinDC View Post
you should be getting you advice from Ted at Soundproofingcompany.com. You will also save money.

forget about Homasote , you can't beat damped mass for isolating bass frequencies.

Two layers of 5/8 with Green Glue.
I plan on calling Ted, thanks. My goal is to do two layers of 5/8 with GG, if I can find a drywaller around here to do it. First subcontractor I talked to was inflexible on how he wants to do the job. He's not getting the job.

I looked up the Homasote and yeah, apparently it won't do the job. Unfortunately as I research STC ratings, they don't apply below a certain frequency i.e. heavy bass, and that's what I'm more concerned about than anything else. Double rock will help due to its mass but BassThatHz did that and he said bass still went right through it.
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Old 07-27-2014, 12:41 PM - Thread Starter
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Originally Posted by BIGmouthinDC View Post
build the media closet after the theater shell is built, so the entire space is inside a soundproofed drywall bunker.
Too late unfortunately. All the framing is done. I may just have to live with putting the rack inside the media closet with no access unless I open and go through the media closet door. Fortunately that side faces the family room and our house is U shaped, so the kids' bedrooms are on the opposite side of the house. I'm more concerned with sound leaking out through the exterior walls and bothering my neighbors.
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Old 07-27-2014, 03:49 PM
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. Double rock will help due to its mass but BassThatHz did that and he said bass still went right through it.
I know for a fact that it works, of course triple rock takes it one step further, see curve frenzy. As a general rule in my experience whenever someone says they did something soundproofing related and it didn't work, their overall strategy was flawed, They did double rock, but not on clips and channel
They left recessed lights in place and didn't address every single wall penetration
They did the ceiling but not the walls
They didn't address HVAC
Poor door
floor?
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Old 07-27-2014, 04:02 PM - Thread Starter
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Originally Posted by BIGmouthinDC View Post
I know for a fact that it works, of course triple rock takes it one step further, see curve frenzy. As a general rule in my experience whenever someone says they did something soundproofing related and it didn't work, their overall strategy was flawed, They did double rock, but not on clips and channel
They left recessed lights in place and didn't address every single wall penetration
They did the ceiling but not the walls
They didn't address HVAC
Poor door
floor?
I read through his entire thread and he finally cut the bass down by tearing the exterior skin off his sound room and adding multiple layers of OSB, etc. He already had double walls, double doors, seals, etc. AFAIK he did everything right. There was no high frequency sound leakage. It was the low bass from something like 8 subwoofers that was the issue.

STC does not apply to low and ultra low frequencies correct?

Right now, I'm willing to give up the access to my stereo rack and not have another fenestration. I'll have to go through a door but at least the sound will have a true barrier. The media closet itself will probably need double rock with GG on the inside since I can't do the clips/channels. But on the outside I'll have double rock, GG, and clips/channels. The media closet can then act as a giant air cavity with double rock on both sides. On the theater door, I can even install another door since the entry way is a very small hall that one can either enter the theater or my study.
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Old 07-29-2014, 04:01 PM
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Did you end up talking to Ted yet? Let me know as I have a few resources from him that might be beneficial to you.
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Old 07-30-2014, 06:46 AM
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Quote:
Originally Posted by video1 View Post
We're converting the garage into a home theater as part of our total house remodel. So #1 , cost is an issue due to all the cost overruns on the rest of the job. If it were up to me, I'd leave the garage as it is with open stud walls and do this part of the project later. But apparently we have to close it up to pass final inspection.

I've attached a copy of the layout of the home theater. I've read through a ton of stuff on this forum and on Sound Isolation Company's website. Yesterday I met with one of the drywall subs who's bidding the project. He didn't seem very flexible on how to sound isolate. His idea was to use the hat channels secured DIRECTLY onto the studs. No clips. Hmmmm. Then he said that the cost of doing double layer of 5/8" sheet rock with Green Glue was going to be higher than the cost of a single layer of Quiet Rock 500 with the acoustical sealant and putty pads. At least he knows about putty pads! He quoted about $100 per 4x8 sheet of Quiet Rock installed. We need about 40 sheets in this 21x19x9.5 room.

I plan on building a couple of 18" subs. I know sound isolation works really well for high frequency sound waves, but many have stated that low frequency long wave bass tends to go right through most stuff. For that heavy mass such as mass loaded vinyl is preferred. But that stuff is very expensive.

Some questions:

1) I just learned about another product - Homasote 440 which has an STC of 55. This stuff looks very promising, and it's less than 1/2 the cost of the Quiet Rock. Does anyone have experience with this stuff? http://www.homasote.com/Installation...highlights.pdf

It would go over the clips and channels and then a layer of sheet rock would go over on top of that. Has anyone had experience with this product?

2) The other issue is our media closet. Current plans are for a door to enter the media closet from the side of the theater. The biggest issue is the equipment rack is going to face the theater so that's a giant fenestration allowing sound to leak right through. We could sound isolate the media closet itself, but clips and channels will be very difficult to use in such a small space.

Would it be more practical to just turn the stand 90 degrees so that it can only be accessed by opening the closet door? Everything could run off an IR repeater. This way at least we have a good wall to isolate the sound and not have an fenestration for the rack.

3) Finally, the former garage door is going to be a solid wall, except I'd like a 36" door for ease of getting stuff into and out of the theater. I don't want to drag stuff (especially construction materials) through the rest of the house. I know heavy mass is better. MDF is preferred over foam. I plan on getting spring loaded bottom of door sealer, and perimeter sealer. I might even cut a piece or two of Homasote 440 and overlay it onto the door on the inside and then cover that with some acoustic cloth. So I'm looking for an exterior door, 36" x 6'8", that's best suited for sound isolation. Are there preferred doors for this kind of application?
Hi Video1,

I answered your question in yesterdays google hangout. You can see the answer to your question here:

I hope it helps.

Thanks
Dennis
Acoustic Engineer
AcousticFields.com
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Old 07-30-2014, 09:54 AM - Thread Starter
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Originally Posted by rdalal1612 View Post
Did you end up talking to Ted yet? Let me know as I have a few resources from him that might be beneficial to you.
Yes, he recommended the clips/channels with double rock and Green Glue. Walls can be simply filled with R13 fiberglass insulation.

He recommended the ceiling lights be sealed cans with remodel housings.

I'm still concerned about bass coming through with all of these layers.
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Old 07-30-2014, 10:08 AM - Thread Starter
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Hi Video1,

I answered your question in yesterdays google hangout. You can see the answer to your question here:
http://youtu.be/Z5zHji4lGcg

I hope it helps.

Thanks
Dennis
Acoustic Engineer
AcousticFields.com
Thanks for taking the time to actually record a video! I'm a bit confused however. You stated correctly that there's not much one can do to trap the bass frequencies below 150Hz, and that maybe I should reconsider dual 18" subs.

But you did not really get into what I could as a solution for the space. Because this is a garage space being converted, we are limited by the envelope of the building. The conversion was added on to our whole house remodel so I really couldn't have planned anything out further any sooner. I'm not sure what else we can do other than what's been already recommended here on the forums.
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Old 07-30-2014, 12:46 PM
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Wow. That guy in the video was something else. Very condescending and never gave a single idea how to help the situation. Oh my bad - I guess he did make a couple suggestions: fewer/smaller subwoofers or, my personal favorite, make less noise in the theater. Did he seriously say that?!?! I'm surprised he didn't suggest you just use headphones. Problem solved!

And was it me, or was he going to say the Green and double drywall are crap?
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Old 08-01-2014, 03:33 AM
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Wow. That guy in the video was something else. Very condescending and never gave a single idea how to help the situation. Oh my bad - I guess he did make a couple suggestions: fewer/smaller subwoofers or, my personal favorite, make less noise in the theater. Did he seriously say that?!?! I'm surprised he didn't suggest you just use headphones. Problem solved!

And was it me, or was he going to say the Green and double drywall are crap?
Sorry you feel that way. I'm trying to offer my thoughts based on 30+ years in acoustics and building. I prefer not to sugar coat the seriousness of the issues people are facing. I do not believe it will do them any good.

Chief Acoustic Engineer at Acousticfields.com. Listen to your music...without hearing your room!
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Old 08-01-2014, 05:04 AM
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Damped Drywall (two layers of 5/8 with Green Glue) on isolation mounting is one key to containing the sound and subwoofer rumble. I've Built them that way many times and it works. Just another guy working in the industry with hands on theater experience. Get as many sub-woofers as you want, prefereably 4 and place them according to the the JBL/Harmon research.
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Old 08-02-2014, 03:43 PM
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I read through his entire thread and he finally cut the bass down by tearing the exterior skin off his sound room and adding multiple layers of OSB, etc. He already had double walls, double doors, seals, etc. AFAIK he did everything right. There was no high frequency sound leakage. It was the low bass from something like 8 subwoofers that was the issue.
I've made it through 1/2 the build thread, not sure why he stuck it over in the speaker forum, that means I missed it and couldn't correct him on the two significant errors he made in the original construction.

RC2 channel is not an acceptable room within a room isolation method it is too firm (rigid) of a connection between the drywall and the structure's framing, of course the vibration is being transferred to the outside.

His method of applying the Green Glue has me scratching my head, there are many areas where he scraped it too thin to be of any value.

IMHO he didn't do everything right as you stated. I stand by my original statement, if you do things right it works.

Last edited by BIGmouthinDC; 08-02-2014 at 03:49 PM.
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Old 08-02-2014, 04:14 PM - Thread Starter
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OK BIG, you're making me feel a little bit better. I'm been so worried that since STC ratings don't apply under 125 Hz, and reading posts that long 30 cycle waves will penetrate all my efforts as it was going through butter. Our budget for the whole house remodel is already 100k over where I wanted it to be. So I'm dreading having to put even more money into the theater than I thought I would have to after reading The Sound Proofing Company website, this forum, and a bunch of other websites.

Dennis Foley's AcousticFields.com website is very interesting if you read through it, albeit his products are not cheap. But he claims they work very well. I had a conversation with him and he's actually very knowledgeable. I'm waiting to hear back from him on his thoughts on solutions to my room.

Quote:
Originally Posted by BIGmouthinDC View Post
I've made it through 1/2 the build thread, not sure why he stuck it over in the speaker forum, that means I missed it and couldn't correct him on the two significant errors he made in the original construction.

RC2 channel is not an acceptable room within a room isolation method it is too firm (rigid) of a connection between the drywall and the structure's framing, of course the vibration is being transferred to the outside.

His method of applying the Green Glue has me scratching my head, there are many areas where he scraped it too thin to be of any value.

IMHO he didn't do everything right as you stated. I stand by my original statement, if you do things right it works.
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Old 08-02-2014, 06:48 PM
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Dennis Foley's AcousticFields.com website is very interesting if you read through it, albeit his products are not cheap. But he claims they work very well. I had a conversation with him and he's actually very knowledgeable. I'm waiting to hear back from him on his thoughts on solutions to my room.
Did you expect him to claim that his products do not work . Keep us posted on your experience with AcousticFields.com.
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