Stethoscopes: what are we hearing?

This paper develops an objective methodology to test the audio quality of stethoscopes, classifies stethoscopes into five functional categories, and compares the audio performance of each of the five categories. These categories, based on the manufacturer's recommended use, are basic assessment, cardiology, disposable, high-end cardiology, and physical assessment. The classification into categories is based on the intended performance of the stethoscopes as provided by the manufacturers.