Which has a bigger cup — Bach 17C or Bach 20C?

The Bach 17C 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 17C and Bach 20C?

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

Bach 17C vs Bach 20C

Name: Bach 20C
Brand: Bach

The Bach 17C 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 17C

• Cornet

Finish—

Mouthpiece B

Bach 20C

• 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.