Inventions Inventions and Designs by Rheuben Allen Inter-change-a-bore Clarinet Barrel> Designed by Rheuben Allen and Bob Malone….This barrel has a very fast response especially in very soft playing, excellent tone color and is very stable unlike wood it does not change. You can clearly see the harmonic key I designed at North Texas University over 40 years ago on Dan’s alto.. It is just above the B key… attached to the Front F key….. It makes getting to the Altissimo notes easier and improves technique. (Not that Dan needed any help)I also gold plated this saxophone and put new keys on the upper stack since Dan wore the pearls and keys out….