The barrel joint is an extremely important aspect of the overall acoustical design of the clarinet. It has a profund affect on modal ratios (pitch) and tonal coloration. We can think of the barrel as the "interface" between clarinet and mouthpiece.
Barrel design was dramatically improved with the innovation by Hans Moennig of the inverted cone bore. This is a shape that is suited well to the paradigm of polycylindrical bored clarinets (most Buffets) and the larger bore style mouthpieces preferred by American players.
FOBES barrels feature an inverted cone style bore and are designed to work in conjuntion with FOBES mouthpieces which have a medium large Kaspar style bore. Improvements you can expect with a FOBES barrel are:
1.Closer twelfth intervals
2.Slightly lowered pitch in the tones of the left hand, upper register
3.Focused throat tones
4.Increased resonance and response
All FOBES barrels are made from aged African blackwood with NO RINGS for better resonance and warmth. Occasionally Clark makes some barrels from Cocobolo. The Cocobolo seems particularly well suited for A clarinets.
The A barrel has a unique double taper the bore and is smaller than the Bb barrel. These will work on and fit Buffet, Yamaha, Leblanc and older Selmer clarinets (pre Signature)