Bach 8½A vs Yamaha CR-9ES
The Yamaha CR-9ES has a wider cup diameter, the Yamaha CR-9ES has a larger throat opening.
The internal diameter of the cup, measured at the widest point inside the rim.
Mouthpiece A
Bach 8½A
• Cornet
Cup diameter16.10 mm / 0.6339 in
vs
Mouthpiece B
Yamaha CR-9ES
• Cornet
Cup diameter16.44 mm / 0.6472 in
Best suited for
High-volume projection — open throat for power
Cup Diameter
The Yamaha CR-9ES has a cup diameter of 16.44 mm / 0.6472 in compared to 16.10 mm / 0.6339 in on the Bach 8½A — a difference of 0.34 mm / 0.0134 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.