Date of Award

Spring 2017

Document Type


Degree Name

Doctor of Audiology (AuD)


School of Communication

First Advisor

Melinda F. Bryan


A stethoscope is intended for three main diagnostic purposes: listening to heart sounds, listening to lung sounds, and determining the presence or absence of bowel sounds (Callahan, Waugh, Matthew, & Granger, 2007). Currently, on the market there are two types of stethoscopes for practitioners to choose: unamplified and amplified stethoscopes. Furthermore, there is little research on the sound pressure levels (SPLs) produced by stethoscopes on the market. Therefore, the current study seeks to measure the SPL produced by various popular unamplified stethoscopes and compare those findings to the SPLs produced by amplified stethoscopes. Secondly, the SPL of selected amplified stethoscopes will be compared to attempt to determine which stethoscope provides the most SPL.

Six stethoscopes (three unamplified and three amplified) coupled to KEMAR were used to measure recorded heart, lung and bowel sounds. The results showed that the type of stethoscope (unamplified vs. amplified) somewhat affected the amount of SPL produced. For example, it was found that the SPL of the Littman Cardiology III unamplified stethoscope was comparable to or exceeded that of two of the amplified stethoscopes for heart and lung sounds while the Littmann Classic II unamplified stethoscope was comparable to or exceeded the SPL for one of the amplified stethoscopes for bowel sounds. Clinical implications/applications regarding stethoscope relevance to the practitioner with and without hearing impairment were discussed.