Bach 11A vs Bach 7A
The Bach 7A has a wider cup diameter.
The internal diameter of the cup, measured at the widest point inside the rim.
Mouthpiece A
Bach 11A
• Cornet
Cup diameter15.70 mm / 0.6181 in
vs
Mouthpiece B
Bach 7A
• Cornet
Cup diameter16.20 mm / 0.6378 in
Cup Diameter
The Bach 7A has a cup diameter of 16.20 mm / 0.6378 in compared to 15.70 mm / 0.6181 in on the Bach 11A — a difference of 0.50 mm / 0.0197 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.