Which has a bigger cup — Bach 12C or Bob Reeves 11C?

The Bob Reeves 11C has a cup diameter of 24.80 mm / 0.9764 in compared to 24.50 mm / 0.9646 in on the Bach 12C — a difference of 0.30 mm / 0.0118 in. A wider cup generally produces a fuller, darker tone but requires more air support.

How does cup depth compare between Bach 12C and Bob Reeves 11C?

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

Bach 12C vs Bob Reeves 11C

Name: Bob Reeves 11C
Brand: Bob Reeves

The Bob Reeves 11C has a wider cup diameter.

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

The taper behind the throat leading to the shank. Affects projection and tone character.

Mouthpiece A

Bach 12C

• Trombone

Backbore—

Best suited for

📣High-volume projection — open throat for power

Mouthpiece B

Bob Reeves 11C

• Trombone

Backbore—

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.