Bach 6½AL (large shank) vs Bach 6½AM (small shank)
the Bach 6½AL (large shank) has a larger throat opening.
How deep the cup is, from shallow (brighter, easier high register) to deep (darker, fuller sound).
Mouthpiece A
Bach 6½AL (large shank)
• Trombone
Cup depthDeep
Best suited for
Orchestral playing — large cup for full, dark tone
High-volume projection — open throat for power
vs
Mouthpiece B
Bach 6½AM (small shank)
• Trombone
Cup depthDeep
Best suited for
Orchestral playing — large cup for full, dark tone
High-volume projection — open throat for power
Cup Depth
Both mouthpieces share a deep cup depth, so the sound character from depth alone will be very similar.
Which is better?
Neither mouthpiece clearly dominates the other — the right choice depends on your embouchure, playing style, and the sound you're after. Try both if possible.