Which has a bigger cup — Bach 12C or Bach 18C?

The Bach 12C has a cup diameter of 15.20 mm / 0.5984 in compared to 15.10 mm / 0.5945 in on the Bach 18C — 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 12C and Bach 18C?

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

Bach 12C vs Bach 18C

Name: Bach 18C
Brand: Bach

The Bach 12C has a wider cup diameter.

Overall Comparison Cup Diameter Cup Depth Rim Width Throat Diameter Backbore Finish Material

Surface plating or treatment (e.g. silver plate, gold trim). Affects feel, durability, and appearance.

Mouthpiece A

Bach 12C

• Cornet

Finish—

Mouthpiece B

Bach 18C

• Cornet

Finish—

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.