Bach 8½A vs Bob Reeves 40/C/692s
The Bach 8½A has a wider cup diameter, the Bach 8½A features a deeper cup.
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
Bob Reeves 40/C/692s
• Cornet
Cup diameter15.88 mm / 0.6252 in
Cup Diameter
The Bach 8½A has a cup diameter of 16.10 mm / 0.6339 in compared to 15.88 mm / 0.6252 in on the Bob Reeves 40/C/692s — a difference of 0.22 mm / 0.0087 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.