Recording Heart Sounds

Our site, maintains a "Heart Sounds" gallery, which has audio clips of a variety of heart murmurs and artifical heart valve sounds recorded utilizing a electronic stethoscope (as a microphone), and a Sharp MD-MT15 minidisc recorder. The sounds clips were then downloaded to a PC and sampled and encoded utilizing Sound Forge 4.5. These heart sounds are very low frequency intensive, and of interest, I could not get Sony minidisc equipment (I think because of "automatic gain control") to accurately record the sound. The Sharp unit has "manual" gain settings and a smallish VU meter incorporated into the display panel, that allowed the gain to be set manually.

Jay Tuna, M.D.
Evansville Heart Center
Evansville, Indiana

Note: The Sony's also have a manual gain control mode, it is entered by pushing the record slider and holding it for 2 seconds. -eaw

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