Which has a bigger cup — Bach 12C or Bach 30CB?

The Bach 30CB has a cup diameter of 30.00 mm / 1.1811 in compared to 24.50 mm / 0.9646 in on the Bach 12C — a difference of 5.50 mm / 0.2165 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 30CB?

The Bach 30CB has a very deep cup while the Bach 12C has a shallow cup. Deeper cups favor a darker, richer sound; shallower cups provide more brightness and easier upper register.

Bach 12C vs Bach 30CB

Name: Bach 30CB
Brand: Bach

The Bach 30CB has a wider cup diameter, the Bach 30CB features a deeper cup.

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

The narrowest point at the bottom of the cup. Affects resistance, volume, and tone color.

Mouthpiece A

Bach 12C

• Trombone

Throat diameter5.85 mm / 0.2303 in

Best suited for

📣High-volume projection — open throat for power

Mouthpiece B

Bach 30CB

• Trombone

Throat diameter—

Best suited for

🎻Orchestral playing — large cup for full, dark tone

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.