Countering Audio Feedback Squeals

From: Ron Pellegrino <>
Subject: Countering audio feedback squeals
Date: May 24, 1999

What follows is a message about countering audio feedback squeals to David Scheirman, a leading light in the audio world as you can see from a partial list of his credentials - Director of Tour Sound Marketing, JBL Professional; Past Chairman, Pacific Northwest Section, Audio Engineering Society; Member 1996-97, Board of Governors, Audio Engineering Society; and Program Co-Chairman, First International Conference on Sound Reinforcement (Nashville, TN 1989). Some of you will be interested in reading David Scheirman's excellent response to my essay on "Why are audio engineers the enemies of our ears."


Hi David:

What follows are some thoughts for you and the folks at JBL that might improve your bottom line and public image. The idea is to protect trusting children and inexperienced adults from audio feedback squeal, that awful pain in the ear caused by people misusing common audio gear such as public address systems and the ubiquitous electronic sound reinforcement systems for music. The misuse of microphones, integrated amplifiers, and speakers has reached plague proportions and it's getting worse. [In brief, audio feedback squeal is produced by the creation of a positive feedback loop in the microphone/amplifier/speaker system; this occurs when the microphone is located in a sound field generated by the speaker driven by an amplifier with its level set too high. Unfortunately very few people in the western world have been spared this painful and often dangerous experience.]

Some background first. I recently attended a public show of student performances at a country grade school where my wife volunteers to teach the creative use of reading and literature. To videotape a dramatic production by the children of one of her stories I sat immediately in front of a stage surrounded by children in the audience - kindergarteners closest to the stage and progressively higher grades behind them completely filling the hall. Given the nature of my videotaping task and the cheek by jowl crowd of children, I was positioned just to the side of a audio speaker that pointed directly at five year old children sitting one foot in front of it. My first thought was that this example of audio ignorance on the part of the school administration and teachers bordered on criminal. The children entrusted to the care of those educators were placed directly in the path of danger to their hearing. It was no surprise that due to uneducated use of the equipment there were the usual collection of feedback squeals, young ears stuffed with fingers (of course always after the audio attack), and chagrined adult educators. Imagine how many times this squealing feedback scenario is repeated in schools and meeting places every day in just the United States. Multiply that number by the rest of the countries in the world, the days in a year, and the years in an average lifetime and the squealing feedback scenario amounts to a major factor in hearing loss, tinnitus, eventual medical costs, loss of productivity, and much duller lives. To make matters worse the squealing feedback scenario is also found at all levels of the music world; see my recent piece on the Lincoln Center Jazz Orchestra - "Squealing With Ellington in San Francisco."

Electronic systems that limit levels and break circuits have been commonplace for a long time. Why not build a version of them into every amplifier and speaker system so that feedback squeals are completely blocked? Another valuable feature would be to build intelligence (talking chips) into audio equipment that would automatically be triggered by feedback to instruct and remind users what is proper for the best performance of the gear. It's time for the audio industry to get creative about solving the audio feedback problem. Your electrical engineers will love the charge. Who knows? Those who create the solutions might even become cultural heros in sane sonic circles. Consider partnering with LSI Logic or National Semiconductor, two likely candidates for designing and manufacturing the specialized chips. If companies in the forefront such as JBL fail to take the lead in solving such problems it surely won't be long before the government wakes up and standardizes the necessary safety features. Imagine the great press JBL would get from taking the lead in this matter. Float the idea to your marketing people; my bet is that they would love it too.


Ron Pellegrino


This corroborating response came in the same day I posted the message above.

From: Ron Pellegrino <>
Subject: Re: Countering audio feedback squeals
Date: May 24, 1999

>Yes indeed, Yesterday I & several hundred other people, including many young
>children, were once again subjected to bad sound reinforcement. We were at
>the Museum of Science & Industry, & there was a Guatemalan folk dance troupe
>performing to taped music. Of course the person running the sound system was
>off to the side, out of the main pattern of the mid & hi elements of the
>speakers, & never once ventured out into the audience area to see what the
>sound was actually like. So of course it was painfully bright & strident, &
>much too loud, & would feedback whenever someone stepped up to a microphone.
>Why do people running sound systems (I refuse to call this guy an engineer)
>forget that music is supposed to be a pleasant experience?

>Another rant from Paul Berolzheimer

Unfortunately the problem of what to call them (profanity aside) is not up to us. They call themselves audio engineers and the proper use of language dictates that we avoid laudatory definitions. So we're left with the good, the bad, and the in between. With the current crop of audio engineers the weight is definitely on the bad side. What disturbs me no end is that they often destroy what should be the sort of sweet special experience that you describe in your message.

Ron Pellegrino

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