Which has a bigger cup — Bach 17 or Bach 18C?

Both mouthpieces have virtually identical cup diameters at 15.10 mm / 0.5945 in.

How does cup depth compare between Bach 17 and Bach 18C?

The Bach 17 has a very deep cup while the Bach 18C has a medium cup. Deeper cups favor a darker, richer sound; shallower cups provide more brightness and easier upper register.

Bach 17 vs Bach 18C

Name: Bach 18C
Brand: Bach

the Bach 17 features a deeper cup.

Overall Comparison Cup Diameter Cup Depth Rim Width Throat Diameter Backbore Finish Material

The taper behind the throat leading to the shank. Affects projection and tone character.

Mouthpiece A

Bach 17

• Cornet

Backbore—

Mouthpiece B

Bach 18C

• Cornet

Backbore—

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.