The DB-90 Dr. Beat from BOSS is a metronome that is loaded with sound and drum patterns to make your practice session less mundane and more musical.. DB-30: Dr. Beat Overview It s portable, reliable, and fun to use. The DB-30 helps musicians take their music to higher levels by offering a set of features that .... Dr. Betotte (iOS – $9.99) is the most expensive of the top five, and the most Dr. ..