Bach 11C vs Bach 17C
The Bach 11C has a wider cup diameter.
Mouthpiece A
Bach 11C
• Cornet
Cup diameter15.70 mm / 0.6181 in
Cup depthMedium
Rim width—
Throat diameter3.66 mm / 0.1441 in
Backbore—
Finish—
Material—
vs
Mouthpiece B
Bach 17C
• Cornet
Cup diameter15.10 mm / 0.5945 in
Cup depthMedium
Rim width—
Throat diameter3.66 mm / 0.1441 in
Backbore—
Finish—
Material—
Cup Diameter
The Bach 11C has a cup diameter of 15.70 mm / 0.6181 in compared to 15.10 mm / 0.5945 in on the Bach 17C — a difference of 0.60 mm / 0.0236 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.