November 15, 2012 By Mark Coxon
We were watching Space Shuttle Endeavor fly over Orange County on its way to its final home at the California Science Center, and a strange question arose. An engineer in our office asked if we knew why they sprayed down the Space Shuttle with water the entire time before and during its initial launch.
We all thought it had to be because of the heat of the ignition of the rocket boosters on the launch pad.
We were all wrong.
The water was used to create a barrier between the shuttle and the noise. The water droplets acted as an insulator to keep the 215dB of pressure generated by the launch (sound waves become classified as shock waves over 194dB) from breaking the shuttle to pieces. It was used to isolate sound, and in commercial A/V, white or pink noise is often used to do the same thing in many environments.
To be honest, I had been in A/V for over six years before I ever heard the term “sound masking.” I was familiar with sound isolation techniques practiced to contain sound in one area through the means of decoupling wall materials from the framed structure, or by placing dense insulating material in wall cavities. I was also familiar with acoustic treatments that were used to “tune” rooms and control the reflections of certain frequencies in the space by diffusing or trapping those frequencies with various acoustic treatment products.
Photos: 8 Great Acoustical Treatment Products
Sound masking, however, was a new term for me, one I first heard when doing a large commercial job for CBRE commercial real estate.
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I admit it; I turned to Wikipedia, which actually had a great analogy on sound masking:
Sound masking can be explained by analogy with light. Imagine a dark room where someone is turning a flashlight on and off. The light is very obvious and distracting. Now imagine that the room lights are turned on. The flashlight is still being turned on and off, but is no longer noticeable because it has been “masked.” Sound masking is a similar process of covering a distracting sound with a more soothing or less-intrusive sound.
I thought this was quite fitting and easy for most of us to understand based on what we know about contrast ratios for projection in bright rooms. Sound masking decreases the signal-to-noise ratio, making lower level sounds fade away.
Sound masking represents a great opportunity for integrators in a few ways:
1. In most cases, sound masking systems do not require changes to the building materials. We know how hard it would be to convince a corporate client to install acoustic treatments on the walls and to break open walls to install isolation blankets, etc.
2. It allows the integrator to bring up a unique set of knowledge that their residential and Geek Squad competition will most likely not be speaking to, giving you the “expert” status in the client’s mind.