Bach 2½C vs Bach 8C
The Bach 2½C has a wider cup diameter.
Mouthpiece A
Bach 2½C
• Cornet
Cup diameter16.40 mm / 0.6457 in
Cup depthMedium
Rim width—
Throat diameter3.66 mm / 0.1441 in
Backbore—
Finish—
Material—
Best suited for
All-round versatile — balanced cup for general playing
vs
Mouthpiece B
Bach 8C
• Cornet
Cup diameter16.20 mm / 0.6378 in
Cup depthMedium
Rim width—
Throat diameter3.66 mm / 0.1441 in
Backbore—
Finish—
Material—
Best suited for
All-round versatile — balanced cup for general playing
Cup Diameter
The Bach 2½C has a cup diameter of 16.40 mm / 0.6457 in compared to 16.20 mm / 0.6378 in on the Bach 8C — a difference of 0.20 mm / 0.0079 in. A wider cup generally produces a fuller, darker tone but requires more air support.
Cup Depth
Both mouthpieces share a medium cup depth, so the sound character from depth alone will be very similar.
Throat Diameter
Throat diameters are essentially identical at 3.66 mm / 0.1441 in, so resistance feel will be comparable.
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.