D.I. Y. Home Studio Acoustics

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Rdlicrnni
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Joined: Thu Dec 12, 2019 8:14 pm

D.I. Y. Home Studio Acoustics

Post by Rdlicrnni »

I have built a studio (control room, live room) in 2 rooms of my home. I live close to a major highway and some outside noise (mostly low end from large trucks) gets in. I used 3/4 MDF and fiberglass insulation to seal inside the windows of the live room but I am getting sound from outside through the walls and ceiling. I know that building a room within a room is the best way to stop outside noise. The problem is that I do not have enough space to do this. My live room is only 11'x14'x8' high. I there is some sound block material on the market but it is very expensive. I am considering building complete walls and ceiling out of 3/4" MDF inside this room with 2-3 inches of air space between the MDF and the drywall walls and ceiling. I would build this free standing on the carpet and slab foundation, but not actually attached to the walls or ceiling and seal all the cracks with calk. My theory is that the MDF would stop more of the low frequency trying to get in. The air space would help and the fact that it is not attached to the existing structure would prevent the sound waves from resonating between the 2 structures. Please let me know if you think this would work. Also, if you have any links 2 sites that would give me some low cost D.I. Y. acoustic design idea, I would greatly appreciate it.
Last edited by Rdlicrnni on Sat Dec 21, 2019 10:51 pm, edited 1 time in total.
Gregwor
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Location: St. Albert, Alberta, Canada

Re: D.I. Y. Home Studio Acoustics

Post by Gregwor »

Welcome to the forum!

Please read the forum rules and completely fill out your profile.
I am considering building complete walls and ceiling out of 3/4" MDF inside this room with 2-3 inches of air space between the MDF and the drywall walls and ceiling. I would build this free standing on the carpet and slab foundation, but not actually attached to the walls or ceiling and seal all the cracks with calk.
A room in a room is the cheapest and actually uses the least amount of space to achieve the type of isolation you seem to require. For a true MSM system, I made an easy to use calculator.

Gregwor & audiomutt’s MSM Transmission Loss Calculator Version 2.03

You can mess with different types of materials at different thicknesses and at different distances from one another to quickly see how much isolation you will achieve (under perfect build conditions of course).

The concern I have with your plan is that you say you don't have room for a room in a room construction but then you say that you do plan to build a room in a room out of MDF. Well, you will still need appropriate framing in order to mount the MDF. At an 11' span, I'm guessing that you're going to need to use at least 2x8 joists. So that lowers your ceiling 7 1/4" plus 3/4" for your MDF plus the gap between your existing ceiling and your new joists (let's just say 2" for fun). So, now you are 10" lower.

This isn't the worst. I assume you have some sheathing on your existing ceiling. What you should do is remove that sheathing exposing your joists and subfloor above. This will give you a bigger gap between your outer leaf and your new ceiling. If you then build your new ceiling using John Sayer's inside out method, you will only lose ~2 3/4" of height! Not bad right!?? Now, this is the acoustic height of your room. Visually, you will still be 10" lower. But, are you concerned about how it looks or how it sounds? Clearly, how it sounds is more important. To put your concerns at ease, check out my buddies little drum practice room. He faced the exact same issues as you and with the black fabric on the ceiling, it feels way taller in there than it actually is. And it sounds killer too:

http://www.johnlsayers.com/phpBB2/viewt ... =1&t=21704
My theory is that the MDF would stop more of the low frequency trying to get in. The air space would help and the fact that it is not attached to the existing structure would prevent the sound waves from resonating between the 2 structures.
There is actual theory on how to achieve isolation. I encourage you to dig through this literature before you tackle any major construction as having some knowledge about the topic will save you a lot of money and get you the results that you're after!

http://www.roletech.net/books/HandbookAcoustics.pdf
Also, if you have any links 2 sites that would give me some low cost D.I. Y. acoustic design idea, I would greatly appreciate it.
By acoustic design do you mean isolation or treatment? It sounds like you have an isolation problem so everything I wrote above should get you started.

Greg
It appears that you've made the mistake most people do. You started building without consulting this forum.
Gregwor
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Joined: Wed Feb 01, 2017 6:03 pm
Location: St. Albert, Alberta, Canada

Re: D.I. Y. Home Studio Acoustics

Post by Gregwor »

Oh and I forgot to mention HVAC concerns. Once you have a truly sealed room, you will need to deal with ventilation. That means large strategically placed HVAC silencer boxes and potentially incorporating a designated air handler unit. A lot of people with size restrictions decide to use a ductless mini split to heat and cool their rooms. This allows you to have a smaller ventilation footprint compared to a ducted system. All of the information you need to know pertaining to this subject can be found in abundance on this forum.

Greg
It appears that you've made the mistake most people do. You started building without consulting this forum.
DanDan
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Location: Cork Ireland
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Re: D.I. Y. Home Studio Acoustics

Post by DanDan »

I use MDF to seal windows too. It can bend a little to seal to a non perfectly flat surface under screw pressure.
It is probably not the best value in terms of providing Mass though, I would presume plasterboard is. I note one of the UK boards is claiming 40dB now.
I recommend analysis of the problem with an open mind, ear, and meter.
Is your noise entering via the ceiling, roof, walls, doors, ventilation, holes or weak spots?
You may need to provide a consistent noise source, e.g. a PA system.
A little stick with smooth ends is useful for listening to surfaces for conduction, structure borne sound.
DD
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