AES Section Meeting Reports

New York - January 17, 2012

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Craig A. Kasper has practiced audiology for over 15 years in New York City. He is currently the Chief Audiology Officer for Audio Help Associates of Manhattan. In addition to his clinical responsibilities, Dr. Kasper is the Managing Director for ACS Custom USA, a manufacturer of custom in-ear monitors and hearing protection. The core mission of ACS is education and the prevention of music/noise-induced hearing loss.

About 30 members and guests gathered at Dale Pro Audio to hear a fascinating talk which covered the basic anatomy of the human hearing system, the factors in hearing health, and protection options for audio and music professionals as well as "civilians."

Dr. Kasper described his earliest musical exploits as a two-year-old mastering his Mickey Mouse keyboard and
learning about pitch and intensity. Later, as a high-school bass guitar player, he experienced hearing damage first-hand. His first work at Columbia University Medical Center was to help musicians and music-industry professionals. He told us that noise-induced hearing loss is the number one preventable form of hearing loss.

Other factors in hearing health include genetics, diet, disease and medications. Some individuals experience sudden, irreversible hearing loss due to viral infections. Diabetes can compromise small capillaries and therefore affect the proper functioning of small hair cells in the inner ear. This can seriously retard the transmission of sounds to the brain.

We also learned about "safe time vs. safe level" — the relationship between high-level sounds and the amount of time we are exposed to them. As intensity increases, the amount of safe exposure time sharply decreases (from hours to minutes). In many cases people who have been exposed to loud sounds experience "temporary threshold shift" and find that their hearing sensitivity returns to normal after a short period of time away from those sounds.

Initial noise or music-induced hearing loss is usually detected in the 3-6 kHz range, so that speech sounds such as consonants are immediately affected. Tinnitus, usually described as a ringing in the ear, can be experienced as a variety of apparent sounds, including running water. Some statistics on tinnitus: it is experienced by 50 million Americans; 16 million seek help, and 2 million stop normal day-to-day activities. Tinnitus generators are centrally localized in the brain, and the phenomenon is more apparent in the absence of ambient sounds.

Protection options include putting your fingers in your ears, using solid earplugs, generic-fit filtered protectors, and custom-molded protectors. The last option is the best because it can provide the most comfortable seal and can eliminate ambient sound consistently. These would be fitted by an audiologist, who would take into account whether or not the user will be moving his or her head and jaw while wearing the "plugs" to be sure that the amount of attenuation remains constant. In these cases the relative softness of silicone plugs (vs. hard acrylic) provides a more consistent attenuation. However, too much attenuation might cause the performer to sing and play much louder. The audiologist must discuss this with the performer.

It was pointed out that In-ear Monitors (IEMs) are not hearing protection, as, by design, they are transmitting amplified sound into the ear. Musicians must be trained to adjust these monitors to a lower level than they have been used to with stage speakers or they risk permanent hearing damage.

An extended Q&A period followed the main presentation.

Please go to
to download Dr. Kasper's PowerPoint slides from this presentation.

The New York Section would like to thank Dale Pro Audio for making the meeting space available.

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AES - Audio Engineering Society