Which has a bigger cup — Bach 11½A or Bach 18?

The Bach 11½A has a cup diameter of 15.65 mm / 0.6161 in compared to 15.10 mm / 0.5945 in on the Bach 18 — a difference of 0.55 mm / 0.0217 in. A wider cup generally produces a fuller, darker tone but requires more air support.

How does cup depth compare between Bach 11½A and Bach 18?

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

Bach 11½A vs Bach 18

Name: Bach 18
Brand: Bach

The Bach 11½A 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 11½A

• Cornet

Backbore—

Mouthpiece B

Bach 18

• 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.