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

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

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

How deep the cup is, from shallow (brighter, easier high register) to deep (darker, fuller sound).

Mouthpiece A

Bach 17

• Cornet

Cup depthVery deep

Mouthpiece B

Bach 18C

• Cornet

Cup depthMedium

Cup Depth

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.

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.