About the Loudness of Sounds and the Risk of Hearing Damage

The View from 2006: Since this article was written in 1993, I've done both a lot more thinking about and study of sound and audio levels, decibels and the measurement of levels. Also, my own practices have evolved significantly. So, throughout this quite important article, I have interspersed a fair amount of updated thinking, in italics, just like this. I hope you find it helpful. It sure is a noisy world!

Overview

Because I've spent some time working in psychoacoustics and noise pollution, I get asked a lot about safety in regard to listening levels. Personally, I'm fascinated by loud noises, and I've fired off my share of firearms, hung out at race car tracks (would you believe I once stood there watching a jet-powered dragster light its afterburner from about 20 feet away? -- oh yes, I did cover my ears with my hands, while the dragster got to about 200 mph in about 200 yards before the driver wisely chickened out, turned it off and popped the parachute -- these things are now illegal at drag-strips as too dangerous). The gritty, distorted, brutal and socially irresponsible levels generated by some club bands in some of the funkier Saturday night bars seemed perfectly sensible to me when I hung out in such places, and I never worried too much about damaging my hearing. Happily, my hearing remains normal for my age, which means the extreme high frequencies are beginning to fade some and I've got a little tinnitus, but other than that everything measures OK, there is only a little loss around 4K, and I can still usually tell the difference between a grand piano and a lead vocalist.

The sensory medium in which music exists is sound. One of the principle subjective attributes of sound is loudness, which is a key element of expressive quality in music. With the development of high-output sound systems, contemporary performers who use sound reinforcement can comparatively easily generate sound levels that reach the "threshold of discomfort."* This capability did not exist before about 1960. This "threshold of discomfort" represents the loudest sounds that are possibly useful musically, sort of equivalent to ffff. Now that we can casually and inexpensively generate music with such sound levels, we are faced with a new set of problems, because while such sounds represent highly emotional and intense feelings and are therefore desirable musically, they also present discomfort and danger to both performers and listeners. Rock-and-roll music has flirted with these levels from its beginning, and has used levels between 100 and 120 decibels Sound Pressure Level as a primary ingredient in its recipe for high intensity as a matter of course. It has always thrived on being "bad," and is not about to shed its "life-on-the-edge" intensity or image of reckless abandon. So, these levels are with us as active musical tools for the foreseeable future.

However, as working music professionals, it is essential for our own survival that we understand what these levels are all about, how much risk they represent to us, how we can protect ourselves (and our audiences), and how to work effectively with music that depends on high levels for dramatic intensity. Remember, when we talk about the "threshold of discomfort," we are talking about PAIN and HEARING DAMAGE!!!

Anyway, I thought it might be interesting to share with you a little about what I know about safety and loudness levels. This doesn't have a great deal to do with studio work, because mostly in studios, believe it or not, levels are pretty reasonable, particularly since we've adopted near-field monitoring as a primary technique for listening to our recordings. However, sound reinforcement is with us in spades, many of you are performers, and rock and roll is nothing if not loud.

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