An apparatus combines a plurality of incoming audio signals and outputs a combined audio signal. The incoming audio signals include a music signal, e.g., from a CD or cassette player, and a rhythm signal triggered by a user's heartbeat. The tempo of the rhythm will increase or decrease with the pulse...http://www.google.de/patents/US6230047?utm_source=gb-gplus-sharePatent US6230047 - Musical listening apparatus with pulse-triggered rhythm
