Both factors contribute to the Wagner tuba's reputation for being fiendishly difficult to play in tune.

WSJ: It Takes Brass to Play the Wagner Tuba | By Barbara Jepson | The Ring of the Nibelung

There are larger physical challenges as well, since Wagner tuba players double on the French horn during the "Ring" when needed.

WSJ: It Takes Brass to Play the Wagner Tuba | By Barbara Jepson | The Ring of the Nibelung

In the "Ring, " four Wagner tubas join an enlarged brass section that includes other orchestral rarities like the bass trumpet, contrabass trombone and contrabass tuba, creating "choirs" of gleaming brass.

WSJ: It Takes Brass to Play the Wagner Tuba | By Barbara Jepson | The Ring of the Nibelung