I have recently moved from tenor to bass trombone at band and at the weekend we started looking at The Mask of Zorro. I was handed both the bass trombone part and the Bb bass trombone part. The bass trom part starts in the key of Eb (three flats), with the other Bb instruments in F (one flat, as I would expect), but the Bb bass trom part starts in G. The question is 'am I missing something ?' or should the Bb bas trom part also be in F ? Thanks Amanda.x.