Masters Theses

Date of Award

5-1998

Degree Type

Thesis

Degree Name

Master of Arts

Major

Audiology

Major Professor

James W. Thelin

Committee Members

Jack Ferrell, Samuel Burchfield

Abstract

In the present study fifteen members of the Knoxville Symphony Orchestra were fitted with Etymotic Research ER-15 Musician's Earplugs that were expected to provide uniform attenuation of 15 dB across the range of audible frequencies. ER-15 earplug attenuation was measured using behavioral procedures. The results indicated that mean attenuation was about 7 dB at 250, 10 dB at 500, and approximately 15 dB at 1000, 2000, and 4000 Hz. The average attenuation for the five test frequencies was 12.4 dB for the ER-15 earplug in contrast to the 21.4 dB for an E-A-R plastic foam earplug. Probe microphone measurements were used to determine the amount of the occlusion effect. Sound levels were measured near the eardrum with and without musician's earplugs while the subjects vocalized the phoneme /a/. Mean occlusion effects were 5 dB or less at 250 and 500 Hz while at 1000, 2000, and 4000 Hz the sound levels were attenuated by an average of 5.5 dB. About one-fourth of the subjects noted that the sound quality of their instrument changed with the ER-15 earplugs and about one-fourth experienced difficulty placing and removing the deep canal fitted plugs. Fourteen of the fifteen subjects considered the ER-15 earplugs to be a good investment and used them during loud passages to protect their ears.

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