Oom-pah, Oompah or Umpapa is the rhythmical sound of a deep brass instrument in a band, a form of background ostinato. The oom-pah sound is usually made by the tuba alternating between the root (tonic) of the chord and the 5th (dominant) — this sound is said to be the oom. The pah is played on the off-beats by higher-pitched instruments such as the clarinet, accordion or trombone. Oompah is often associated with Volkstümliche Musik, a form of popular German music, and with polka. In triple time genres such as the waltz it is oom-pah-pah.