Which has a bigger cup — Bach 18C or Bach 20C?

The Bach 18C has a cup diameter of 15.10 mm / 0.5945 in compared to 15.00 mm / 0.5906 in on the Bach 20C — 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 18C and Bach 20C?

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

Bach 18C vs Bach 20C

Name: Bach 20C
Brand: Bach

The Bach 18C has a wider cup diameter.

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

The width of the rim surface that contacts the lips. Wider rims improve endurance; narrower rims improve flexibility.

Mouthpiece A

Bach 18C

• Cornet

Rim width—

Mouthpiece B

Bach 20C

• Cornet

Rim width—

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.