Bach 12E vs Bach 15E
The Bach 12E has a wider cup diameter.
The taper behind the throat leading to the shank. Affects projection and tone character.
Mouthpiece A
Bach 12E
• Trombone
Backbore—
Best suited for
High-volume projection — open throat for power
vs
Mouthpiece B
Bach 15E
• Trombone
Backbore—
Best suited for
High-volume projection — open throat for power
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.