A few words on acoustics

by | Studio Equipment

I belong to a voice actors newsgroup and would like to share one of its threads. Since I only know first names, I can’t credit the sources, but the information  and related urls are may be of benefit to some.

Hello everyone! I’ve got an issue I’m trying to work out. Right now, 
I’m taking the cheap path to making a small room a voice-recording 
booth by adding in foam crate sheets (queen size to be exact) but I 
came across Acoustical Ceiling Tiles at Lowe’s that say that reduce 
sound by 55%, etc, but they are the 2’x4′ or 2’x2′ tiles that you 
usually see in class rooms and business offices. Can this sort of
thing hang on a wall instead of foam, or would it be considered a
health hazard in anyway? Has anyone ever considered this option?

A: The first thing you need to do is define what you mean by sound proofing.

Are you trying to keep unwanted sounds out, or reduce the echo
or flatten the acoustics in the room?

If you are trying to keep noise out there are only 3 things to stop noise:
Space: distance
Mass: concrete walls are best
Dampening: retarding vibration lead is best for this or mass loaded vinyl (MLV).

Noise Reduction vs. Noise Absorption
Noise Reduction is achieved by stopping it, killing it, not letting the noise get through the
wall or window. Stop the noise before it gets to you, or into the room you are in. For this
you use mass and space. You can build heavy walls with large air spaces and you
maximize dampening as best you can. Two layers of drywall will do the trick with a layer
of MLV in between.
Noise absorption is achieved by changing the characteristic of the noise. Stop it from
echoing. Stop the reverberation. Stop the noise reflections. All this involves handling the
noise that is within the room. It seldom involves noise from outside the room. You have
likely heard of a room as being a “live” room or a “dead” room. For this type of noise
reduction or soundproofing you will use carpets, upholstered furniture, acoustical ceiling
tile, soundboard or interior walls. Panels made with 4″ of Owens-Corning 703, in wood
frames covered in cloth work great.
What works for noise absorption does not ever work for noise reduction. Soundboard is
useless at stopping noise. When put up with the sheetrock it is useless unless it is the
outside layer and it is being used for noise absorption sound control.
Here are some sites that may help you out:


  1. Bobbin,

    Thanks for the great post. I like the fact that it makes a clear seperation between noise reduction and noise absorption. I get that question a lot. I’ll refer others here.

  2. Hi Dave,

    I appreciate your comments. I have thought  and learned a lot about noise reduction vs. absorbtion, especially while designing my new sound booth. Thanks for stopping by!
    Best, Bobbin

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