Your Hearing Is Priceless

by Karen Kalish

"Advances in technology, computerization and an increase in consumerism have all contributed to a steady increase in the volume of sound in our environment. The general public remains unaware that permanent high frequency hearing loss may occur due to overexposure to excessive sound levels, irrespective of the source," says Dilys Jones, of the House Ear Institute, an international leader in hearing research, which has been advocating hearing conservation to professionals in the recording arts and sciences through its Hearing Is Priceless educational program.

"These days digital sound, with its increased dynamic range, offers volumes that, if not regulated, can be painfully loud," states Corey Bailey, N.T. Audio's General Manager. "And recently, the film-going audience has also begun to notice and comment on the loud levels. This situation has escalated to the point where CD players are being manufactured with volume-limiting circuits to protect our children's hearing and dubbing mixers are being issued specialized ear plugs."

Educational workshops and seminars have been hosted by the Cinema Audio Society, the Audio Engineering Society, the National Academy of Recording Arts & Sciences and the SMPTE. The results of some of these studies will be available at a later date.

The Basic Facts

The following is information made available by the House Ear Institute. Sounds of sufficient volume and duration can damage the sensory cells that line the walls of the hearing organ (cochlea) and result in temporary or permanent hearing loss and sometimes tinnitus (head noise). At first the loss is unnoticeable, with only the highest frequencies of the human hearing threshold affected. However, repeated exposure to loud sound for long periods of time can cause additional nerve damage until eventually the mid-range, where speech sounds are discerned, is affected and one's ability to communicate is impaired.

Warning signs of overexposure to loud sound include a temporary threshold shift, a ringing or buzzing sound in the ears, ear pain or discomfort after exposure or difficulty in noisy environments.

Preventive Measures

This type of hearing loss is cumulative and permanent, but usually preventable. OSHA guidelines state that if an individual is exposed to sound levels above 85dBA for more than eight hours at a time, hearing conservation measures should be taken. It is suggested that professional sound engineers regulate their sound levels as much as possible, increasing the levels only when necessary. Alternatively, hearing protection devices that have maximum attenuation (reduction in amplitude or level of a signal) at high frequencies or custom ear plugs that boost high frequencies to flatten attenuation may be worn. Another option is to remove oneself from the loud sound environment and treat ones ears to fifteen minutes of silence every few hours, allowing the sensory cells time to recover.