12 Famous Jazz Duets for Horn, volume 1 by Randy Aldcroft â¢ Randy Aldcroft has written 3 volumes (12 in each volume) of wonderful jazz duets for Horns in all keys. â¢ Volume of the duets was written for the intermediate and advanced student interested in learning to play in a jazz style. â¢ The range of notes gets higher and the duets get harder with each volume. â¢ The chord changes are included to help learn the structure and chord progressions, and so the duets may be played with a rhythm section if desired, but there is no improvising... all notes are written out. â¢ These duets are perfect for the student and teacher to work on at lessons and several of them can even be programmed together as a medley on a concert or recital.