Which has a bigger cup — Bach 10½A or Bach 9?

The Bach 9 has a cup diameter of 16.05 mm / 0.6319 in compared to 15.90 mm / 0.6260 in on the Bach 10½A — a difference of 0.15 mm / 0.0059 in. A wider cup generally produces a fuller, darker tone but requires more air support.

How does cup depth compare between Bach 10½A and Bach 9?

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

Bach 10½A vs Bach 9

Name: Bach 9
Brand: Bach

The Bach 9 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 10½A

• Cornet

Backbore—

Mouthpiece B

Bach 9

• 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.