PUBLICATION: Electronic Musician
DATE: June 1996
SECTION: page 75
BYLINE: Diane Lowery
ACTIVISTS, INDIVIDUALS, AND GROUPS MENTIONED: H.E.A.R. (Hearing Education and Awareness for Rockers), EAR ProTech, The House Ear Institute-- audiology centers
Electronic Musician reports that hearing damage and hearing loss can happen to young and elderly people alike. Hearing damage is permanent, yet usually preventable, provided that you are aware of how to protect your ears. Visiting a trained audiologist and using the proper ear protection can help prevent hearing damage, or help prevent further damage if some has already occurred. Musicians, their assistants, and anyone else exposed to repetitively loud noises need to take special precaution.
The human ear is constructed of three parts: the outer ear, middle ear, and inner ear. The outer ear serves as a funnel to capture sound and send it to the middle ear, which transmits the sound mechanically into the inner ear. Tiny hair-like cells oscillate in the inner ear in response to vibrations, and then transmit the vibrations as signals to the brain through nerve endings. If these cells are exposed to long and repeated loud sounds, they can become permanently damaged.
Sound can be measured in terms of frequency or pitch and amplitude or loudness. Pitch is our perception of the rate, or frequency, of the vibrations that make up sound waves. Faster vibrations create higher pitches and slower vibrations create lower pitches. The rate of vibration is measured in cycles per second (Hz) or thousands of cycles per second (kHz). Loudness, or our perception of the intensity of the sound, is measured in units of sound-pressure called decibel (dB SPL). A healthy ear comfortably hears from 0 dB SPL to 85 dB SPL. Human ears are not equally sensitive to all frequencies, so the dB SPL scale is weighted to compensate. The A scale (dB A) is the most common standard of weighting. Some live music registers at 120 dB A, causing pain in our ears, and repeated exposure to sounds over 90 dB A can lead to hearing loss.
Hearing loss happens gradually, but can sometimes be detected by a number of symptoms. One of the most common symptoms is tinnitus, a ringing in the ears. Another symptom is a threshold shift, which means you can't hear as well as usual after being exposed to loud sounds. Sounds may seem they are coming to you from underwater or far away. If a threshold shift recurs, the hearing loss becomes permanent. Diann Smith, an audiologist with EAR ProTech (tel. 714-646-2676), explains: "When testing someone who has noise induced hearing loss, his or her hearing is normal from about 25 Hz to 2,000 Hz. But when it hits 4,000 Hz, hearing ability takes a nose dive. Then at 8,000 Hz, he or she can hear well again." An example of this kind of loss is being in a crowded room and hearing people talking, but not being able to exactly understand what they are saying. The consonants such as t, p, b, and k can be lost because they are carried at around 4,000 Hz. Another symptom of hearing loss is a distortion of pitch perception, as when each ear perceives the same tone differently. Recruitment, yet another symptom, is a change in your perception of loudness. Soft sounds are difficult to hear but increasing the volume quickly makes the sound painful to hear.
To help prevent the types of hearing loss described above, you may visit an expert in the field of audiology. The House Ear Institute and H.E.A.R. are two organizations with audiology clinics, who can recommend an audiologist in your area if they are not. They test your hearing and examine your medical and musical history. They also consider nonmusical causes of hearing loss, such as viral infections, or the use of caffeine or legal drugs (such as aspirin) which can cause ringing in the ears. An initial complete hearing test, called a baseline, measures all frequencies up to 18 kHz and is used for later comparison. If the baseline stays the same over a period of time, then whatever preventative measures that have been taken are proved to be effective. A thorough testing up through 20 kHz will ensure that no gaps in the audial spectrum will remain undetected.
Electronic Musician reports that preventative protection is available for musicians, mostly in the form of earplugs. (Editor's Note: Electronic Musician neglected the most obvious solution--turning down the volume.) The first grade of earplugs is the foam ear plugs, inexpensive and available at most drugstores. They attenuate up to 29 dB A but some high frequencies will be lost. The most common error in using foam ear plugs is not inserting them far enough into the ear canal, reducing the protection. Doc's Proplugs (distributed by International Aquatic Trades, Inc.) are a more sophisticated ear plug that comes in eight different sizes, ready to wear. A vent in the filter of the ear plug controls the amount of attenuation. ER 15 and ER 25, which go down and around the curves of the ear canal, are custom-made ear plugs for performing or recording musicians. The ER 15 decreases the volume but not the frequency range at 15 dB A, as the ER 25 does the same at 25 dB A. Information about variations of these custom ear plugs is available from your audiologist. Personal monitors are also available to musicians, which are miniature versions of stage monitors that are custom fitted for the ears. Within them are tiny speaker elements which receive signals from the stage monitor. However the personal monitor can be as damaging as the stage monitor if the volume is turned up too loud, so specific advice from your audiologist should be sought before using a personal monitor.
Preventative measures can also be taken in conjunction with the use of protection devices. Those who work in the music business should pay special attention to preventing high-decibel feedback, which in some cases can cause immediate and permanent hearing loss. Taking 30 to 45 minutes breaks from recording sessions can also help prevent ear fatigue and therefore hearing damage. Measuring the level of a recording session with a sound-level meter, in conjunction with OSHA (Occupational Safety and Health Administration) guidelines, can provide musicians with the ability to create a less damaging recording environment. And for musicians and non-musicians alike, taking preventative measures in conjunction with wearing protective devices for all excessively loud environments (such as firing ranges, airports, and concerts) can help prevent hearing damage as well. The most fundamental preventative measure you can take is visiting your audiologist and learning how healthy your hearing is.
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