designed especially for musicians and music educators who use music CDs for accompaniment. The PSD340 features both a CD recording drive and an innovative MP3 CD player drive capable of real-time tempo and key control and voice reduction. Slow Down a song while retaining the musical pitch of the original song. Or, shift the key of any song at the touch of a button up or down as much as an octave. Fine tuning allows you to match the tune of the original song to your instrument.