Which has a bigger cup — Bach 12 or Bach 17?

The Bach 12 has a cup diameter of 15.20 mm / 0.5984 in compared to 15.10 mm / 0.5945 in on the Bach 17 — a difference of 0.10 mm / 0.0039 in. A wider cup generally produces a fuller, darker tone but requires more air support.

How does cup depth compare between Bach 12 and Bach 17?

Both mouthpieces share a very deep cup depth, so the sound character from depth alone will be very similar.

Bach 12 vs Bach 17

Name: Bach 17
Brand: Bach

The Bach 12 has a wider cup diameter.

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 12

• Cornet

Backbore—

Mouthpiece B

Bach 17

• 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.