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

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

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

Bach 12 vs Bach 18

Name: Bach 18
Brand: Bach

The Bach 12 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 12

• Cornet

Finish—

Mouthpiece B

Bach 18

• 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.