Bach 6½AL (large shank) vs Conn Precision 2
Both mouthpieces share similar core dimensions — the differences are in the details.
The internal diameter of the cup, measured at the widest point inside the rim.
Mouthpiece A
Bach 6½AL (large shank)
• Trombone
Cup diameter25.40 mm / 1.0000 in
Best suited for
Orchestral playing — large cup for full, dark tone
High-volume projection — open throat for power
vs
Mouthpiece B
Conn Precision 2
• Trombone
LeadCup diameter—
Best suited for
Solo work; high register; bright
Big bright tone; excellent solo
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.