Stemoscope is an input device, output and sound quality experience depends on the cellphone and earphones. As an input device, the Stemoscope sound quality is very good! You may refer to independent reviews to see how professionals said about Stemoscope. For example, there is a side by side comparison with an electronic stethoscope of a different brand https://www.youtube.com/watch?v=WUjZMZCmKQU. You may also listen to those audio samples we recorded with Stemoscope on our Youtube channel https://www.youtube.com/channel/UCO5TlYi3dtdA7Yfp_6KdW8A. According to some comments from who listened to the Stemoscope sounds, the Stemoscope sounds are very natural and very close to what heard with a classic stethoscope.