Bach 12E vs Conn Precision 1
the Conn Precision 1 features a deeper cup.
The internal diameter of the cup, measured at the widest point inside the rim.
Mouthpiece A
Bach 12E
• Trombone
Cup diameter24.50 mm / 0.9646 in
Best suited for
High-volume projection — open throat for power
vs
Mouthpiece B
Conn Precision 1
• Trombone
OrchestralCup diameter—
Best suited for
Large bore trombones; symphony work
Good clear tone; large bore symphonic
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.