Kelly 5C vs Yamaha CR-14ES-GP
The Yamaha CR-14ES-GP has a wider cup diameter, the Yamaha CR-14ES-GP has a larger throat opening.
The internal diameter of the cup, measured at the widest point inside the rim.
Mouthpiece A
Kelly 5C
• Cornet
GeneralCup diameter16.76 mm / 0.6598 in
Best suited for
High-volume projection — open throat for power
Mid-range all-purpose
vs
Mouthpiece B
Yamaha CR-14ES-GP
• Cornet
Cup diameter16.86 mm / 0.6638 in
Best suited for
Orchestral playing — large cup for full, dark tone
High-volume projection — open throat for power
Cup Diameter
The Yamaha CR-14ES-GP has a cup diameter of 16.86 mm / 0.6638 in compared to 16.76 mm / 0.6598 in on the Kelly 5C — a difference of 0.10 mm / 0.0039 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.