I would recommend a spray for the ducts outside. It may be too late. Although if they're in place... can spray on them too.
Dedicated audio room build thread aka The Big Dig
- Thread starter HughP3
- Start date
This stuff because it can take higher heat than anything you could apply to the outside that is suppose to stick but might droop off.
Works fine in my response. Just click on it. But here's the URL https://www.secondskinaudio.com/car-soundproofing-packages/spectrum-spray-kits
Fired up the furnace and dehumidifier today. Need to dry out the structure before some of the carbon arrives next week. Very pleased with sound level as there was almost none. Peak iPhone dB was 38 with average at 35.
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after a bit of a lull, took delivery of 50 pre built boxes from another persons project ( only leaves 260 for me to build 
). Some pics of the install. The missing spaces are due to a 14.25” box and less than that in the stud space. Fortunately I have a commercial band saw that can rip the 1/8 to 1/2” off. Nothing ever bolts on is an old saying in the car world and holds true here...
). Some pics of the install. The missing spaces are due to a 14.25” box and less than that in the stud space. Fortunately I have a commercial band saw that can rip the 1/8 to 1/2” off. Nothing ever bolts on is an old saying in the car world and holds true here...Attachments
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after a bit of a lull, took delivery of 50 pre built boxes from another persons project ( only leaves 260 for me to build
It looks like you added another 3/4" of furring strips on top of the 2x12s?! Im assuming that you needed more depth to allow for the 3.25 or 2.25 space on each side of the carbon box?
Im curious that the OSB wood infill layers are caulked to fill in the cracks against the 2x12s, but the sides of the 2x12s where they meet the top and bottom are not caulked. Seems like either both would be caulked to control vibration/sound or neither would be, if it were irrelevant to performance.
Is it a problem that the 50 carbon boxes have a 1"ish gap at the top or bottom?
This design is really fascinating, I had pinged Dennis back a couple months ago about building a CAW or two in my room, but delayed because of the significant effort involved. The amount of work you have done is unbelievable. Truely world class. I Hope to circle back based on your experience. His carbon tech is interesting to me.
Not knowing where you are building this dedicated listening room / building please take my comment with a grain of salt.
With the HVAC system being outside I would think that enclosing the metal duct work so that it would not be subjected to the elements would make the HVAC system going into your listening room quieter. Also if a "rubber flexible duct transition " where to be installed it would bring down mechanical noise as well. This may have been installed ?
My room is 24 db with AC system on. Heating my room with hydronic tubing which is in the concrete slab. I believe that the lower the noise floor is the better the music will sound.
The carbon system that you are using is very intriguing and interesting. Have been following this thread since day one.
Thanks for sharing.
With the HVAC system being outside I would think that enclosing the metal duct work so that it would not be subjected to the elements would make the HVAC system going into your listening room quieter. Also if a "rubber flexible duct transition " where to be installed it would bring down mechanical noise as well. This may have been installed ?
My room is 24 db with AC system on. Heating my room with hydronic tubing which is in the concrete slab. I believe that the lower the noise floor is the better the music will sound.
The carbon system that you are using is very intriguing and interesting. Have been following this thread since day one.
Thanks for sharing.
Jturbo thanks for following and I appreciate your input. Btw are you a car guy ie turbo?
Yes had to add 3/4 furring. Per Dennis he said the walls have to be 12 inches thick for the air space he wanted. Well lumber does not come that way,
. A typical 2x12 is actually 1.5 x 11.25. We had a talk about dimensional lumber vs his specs. He acknowledged the issue but clarified that 12 inches was a must, hence the 3/4” furring. The boxes are not exactly filling the Spaces because the framers did not follow my measurements as they should have. I had already built a lot boxes before hand. By the time I measured what they had done (they did a lot in one day) it was too late. Speaking with Dennis he said it was not a big deal as long as I was within 3 to 4 inches which I am.
I have only caulked the middle layer. If there was no gap I did not caulk that area. I bet I will spend $1k just on caulk.
Here is my first shipment of carbon. This pallet is 1500lbs. After filling one of my filters, I calculated I need another 7000lbs to finish it all. I am doing it myself as framers had to move to another job for a length of time. They recommended one guy but his per box rate came out to about $80 per hour, really
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Rugby think you for following also! And thank you for the advice.
I just remeasured with my I phone. All systems off. My site has no external noise, not close to any roads or any other homes. My iPhone recorded 33DB, with was dead quiet. So that’s the baseline. To be fair, the ductwork coming through the building has not been caulked yet. There are gaps of a quarter inch to half-inch through the wall which will be sealed. That will help. There is no 3/4 “ paneling installed nor is there carpet over the slab yet. Even with those gaps, Turning on the AC I recorded 36 to 38DB. Honestly I heard nothing from the vents. Only thing a could hear or really feel was a very low grade vibration. My breathing spiked the phone more. I will remeasure when the room is finished out. Anyhow, I listen at 90db with peaks over 100. You bet if the hvac system becomes an issue I will take care of it.
Thanks for taking your time to post!
Any chance we could get a picture of one of the bags of carbon? I'm curious where Dennis sources the carbon from.
Yes I had done the same thing in my previous room. I had Maggie 20.7, took all the 2" Fibreglass panels out and the room came alive. Dennis has promised no over damping. I will have panels but his foam is not typical stuff. Thanks for taking the time to commenting.
JT - i now see what you mean and I will go back and caulk the 2x12’s as needed. Thanks for pointing that out.
Turbo is just a play on my last name.
Cool. That made sense to me. Any idea if rhe type of caulk used was important in the process?
I used Green Glue sealant. Tried some others but this stuff stays pliable vs brittle. It’s taking many many tubes given all the joints.
Wondering. Since the 2x12 cavities were made taller than you were planning. Are you planning on mounting the 4x8 sheets of finished plywood horizontally? Is it going to be a problem that the long edge of the sheets look like they will be shorter than the height of each cavity ( IE the seam of the sheet will not land on the horizontal 1x3)? As you stack the sheets of plywood it seems very few of the seams will land on the sub structure excepting for the 16" OC vertical members.
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