An adapter system that converts an in-line microphone to a stethoscope is described. The adapter includes a grooved channel, a rear cap, a front diaphragm, a recessed surface and a sound tunnel. The grooved channel may be disposed in a base. The grooved channel receives the in-line microphone. The lid covers the grooved channel and the lid is removably coupled to the base. The front diaphragm contacts a listening surface. Also, the front diaphragm is coupled to the base. The recessed surface is disposed adjacent to the front diaphragm. The sound tunnel includes a sound tunnel entrance proximate to the recessed surface. The sound tunnel extends to the grooved channel. The recessed surface and the sound tunnel capture sound vibrations received at the front diaphragm and transmit the sound vibrations through the sound tunnel to the in-line microphone disposed in the grooved channel.