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

The Bob Reeves 11C has a cup diameter of 24.80 mm / 0.9764 in compared to 24.13 mm / 0.9500 in on the Kelly 12C — a difference of 0.67 mm / 0.0264 in. A wider cup generally produces a fuller, darker tone but requires more air support.

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

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

Bob Reeves 11C vs Kelly 12C

Name: Kelly 12C
Brand: Kelly

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

Bob Reeves 11C

• Trombone

Backbore—

Mouthpiece B

Kelly 12C

• Trombone

Lead

BackboreS

Best suited for

📋Lead trombone; smallest cup

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.