Boss DB-90 Dr. Beat Metronome The BOSS DB-90 metronome packs an astounding number of functions and features into its compact, lightweight chassis. You get four great metronome sounds (including human voice) plus dozens of drum patterns to accompany your playing. Easily customize rhythms with the Note Mixing function for a great variety. Use the built-in mic, MIDI input, and direct guitar input onboard the DB-90 for all types of practice sessions, or plug in your Roland V-Pad and work with the Rhythm Coach function. Finally, users find the DB-90 easy to use with the adjustable sliders, buttons, rotary knob, and large backlit LCD.