Author Topic: Bass is still traveling out of soundproofed room  (Read 8677 times)

mpviss

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Bass is still traveling out of soundproofed room
« on: February 24, 2011, 10:50:12 PM »
Hi,

I recently built a "room within a room" in the basement of my row house for my band to practice. It consists of 4 walls, with one door, no windows, and a drop ceiling. Each wall is 6-10 inches off of the outer cinder block walls, and each wall has a layer of sheetrock on the outside attached with resilient channel. There is fiberglass insulation in each wall, and the interior portion of the wall is MLV sandwiched between two layers of sheetrock, hung with resilient channel (lined with foam tape). The ceiling is one layer of MLV above one layer of sheetrock, attached with resilient channel. The floor is carpeted cement, not floating.

In general the room works great but the bass, and bass drum can still be heard from inside the neighbor's house. Is there a good way (the cheaper the better of course) to reduce specifically low frequency sound transmission through the walls?


Randy S

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Re: Bass is still traveling out of soundproofed room
« Reply #1 on: February 25, 2011, 03:42:15 PM »
why did you put in a drop ceiling? "Room in a Room" includes the ceiling to be built like the walls...
Randy Sieg

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mpviss

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Re: Bass is still traveling out of soundproofed room
« Reply #2 on: February 25, 2011, 09:48:37 PM »
Drop Ceiling may be the wrong name for it. My parlance isn't perfect. The ceiling is constructed as described for height reasons. The basement is not dug out so the ceilings were barely 8' to begin with. One of the band members is 6'6" tall so keeping some height was important. The ceiling is attached with resilient channel so it is not directly connected to the joists. As I mentioned, almost all the sound is contained, but the bass seems to travel through the walls. I am not sure a different ceiling would drastically effect that problem but I am not an expert so I could be wrong.

Randy S

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Re: Bass is still traveling out of soundproofed room
« Reply #3 on: February 25, 2011, 10:13:17 PM »
ok the problem could be from a couple reasons, first thing to address would be the floor. The concrete is a great conductor of impact and bass. You can use MLV w/Closed cell foam or 2lb MLV, this will help reduce the impact and bass getting to the concrete.Keep in mind that just decoupling the drums from the floor is not the entire solution you still have SPL sound pressure level which also mimics impact to the entire room and those in it.
Since the walls are already built if you had to increase the STC value you could hang another sheet of drywall 5/8" with a 3 tube per 4' x 8' sheet of Green Glue dampening compound to the walls and ceiling. Do the floor first then assess the reduction.

Question: 1)In the space between the cinder block walls and the outer drywall do you have insulation? 2) is it sealed? 3)  and is there any windows in the basement wall?


Randy Sieg

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888-942-7723
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Fax.760-752-3040

mpviss

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Re: Bass is still traveling out of soundproofed room
« Reply #4 on: February 26, 2011, 08:33:17 PM »
Thanks for the advice. I was suspicious that the floor would be a problem. In the space between the walls there is no insulation and there is one window facing the front of the house. It is not sealed, except for a piece of drywall over the spaces to keep the cats from getting lost in the in between space. I am not too worried about the sound traveling out the window, or even being heard within the house. My main concern is that the neighbors not hear the music from within their house, to avoid complaints.  I had hoped not to spend more money on even more MLV since it is expensive but I would like to do the project right. Is the MLV on the floor going to have a larger effect than an additional layer of drywall? Also, would building a drum platform and a bass platform in addition to laying MLV on the floor help?

Thanks again for your help so far.

Randy S

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Re: Bass is still traveling out of soundproofed room
« Reply #5 on: February 28, 2011, 04:09:18 PM »
Yes the MLV will make a huge difference over drywall, and the drum platform will help with direct impact to the floor. Make sure you fill any voids in the stage with insulation and I would advise using 2 layers of OSB with green glue for the stage.

Even though you dont see the window as a problem, it is. Low frequency is a beast and any reverberation on the back side of the room can and will get out through an unsealed window system.

Remember, any time you decouple from the structure you give yourself the best reduction value.
Randy Sieg

Super Soundproofing Co
www.soundproofing.org
888-942-7723
Ph. 760-752-3030
Fax.760-752-3040

whatismisophonia

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Re: Bass is still traveling out of soundproofed room
« Reply #6 on: February 14, 2012, 07:50:55 AM »
Each wall is 6-10 inches off of the outer cinder block walls, and each wall has a layer of sheetrock on the outside attached with resilient channel. There is fiberglass insulation in each wall, and the interior portion of the wall is MLV sandwiched between two layers of sheetrock, hung with resilient channel (lined with foam tape).

Unless im reading this wrong, this sounds suspiciously like a tripple leaf...

Randy S

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Re: Bass is still traveling out of soundproofed room
« Reply #7 on: February 14, 2012, 04:50:56 PM »
Yes you are reading it wrong...let me modify my typo.. hahaha

Randy Sieg

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888-942-7723
Ph. 760-752-3030
Fax.760-752-3040

whatismisophonia

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Re: Bass is still traveling out of soundproofed room
« Reply #8 on: February 15, 2012, 02:52:25 AM »
its youre, not your(with or without the apostrophe) i cant spell for crap, i just thought id finally give you a heads up.  The part where he says "outside" is what's throwing me off. 

johnbergstromslc

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Re: Bass is still traveling out of soundproofed room
« Reply #9 on: February 16, 2012, 11:27:37 PM »
Unless im reading this wrong, this sounds suspiciously like a tripple leaf...

It's not a triple-leaf system, but putting the MLV in between the drywall, in rigid contact, is a mistake - one I made in my early days of 'kinda not knowing what I was doing'...

MLV shoud hang as a limp curtain to be most effective.  It should only be secured around it's perimeter.

whatismisophonia

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Re: Bass is still traveling out of soundproofed room
« Reply #10 on: February 17, 2012, 06:25:15 AM »
well, what i was meaning, is that at first he said each wall had "a" layer of sheetrock attached to resilient channel on the "outside".  Then he goes on to say the "inner portion" of the wall is double drywall with mlv on resilient channel.  I thought he was talking about two different walls, until it dawned on me that he ment the "inner portion" was the mlv.  Is that correct or am i stupid(dont answer that Randy)?