Bach 1D vs Bach 2½C
The Bach 1D has a wider cup diameter, the Bach 2½C features a deeper cup.
The taper behind the throat leading to the shank. Affects projection and tone character.
Mouthpiece A
Bach 1D
• Cornet
Backbore—
vs
Mouthpiece B
Bach 2½C
• Cornet
Backbore—
Best suited for
All-round versatile — balanced cup for general playing
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.