Bach 12E vs Bob Reeves 11C
The Bob Reeves 11C has a wider cup diameter.
The internal diameter of the cup, measured at the widest point inside the rim.
Mouthpiece A
Bach 12E
• Trombone
Cup diameter24.50 mm / 0.9646 in
Best suited for
High-volume projection — open throat for power
vs
Mouthpiece B
Bob Reeves 11C
• Trombone
Cup diameter24.80 mm / 0.9764 in
Cup Diameter
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 12E — a difference of 0.30 mm / 0.0118 in. A wider cup generally produces a fuller, darker tone but requires more air support.
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.