Wolfgang Amadeus Mozart Ed: David Heyes . A welcome addition to the double bass quartet repertoire, this popular choral masterpiece has been newly typeset and edited and is available in two keys - C major/D major - published together. The sustained and chordal four-part writing is ideally suited to the bass quartet medium and it can also be successfully performed by massed bass orchestra.. Performance Level: 6;8.. Grade: 6 - 8