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

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

Bach 11½C vs Bach 18C

Name: Bach 18C
Brand: Bach

The Bach 11½C has a wider cup diameter.

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 11½C

• Cornet

Cup depthMedium

Mouthpiece B

Bach 18C

• Cornet

Cup depthMedium

Cup Depth

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

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.