Bach 11½A vs Bach 11B
The Bach 11B has a wider cup diameter, the Bach 11½A features a deeper cup.
Mouthpiece A
Bach 11½A
• Cornet
Cup diameter15.65 mm / 0.6161 in
Cup depthVery deep
Rim width—
Throat diameter3.66 mm / 0.1441 in
Backbore—
Finish—
Material—
vs
Mouthpiece B
Bach 11B
• Cornet
Cup diameter15.70 mm / 0.6181 in
Cup depthDeep
Rim width—
Throat diameter3.66 mm / 0.1441 in
Backbore—
Finish—
Material—
Cup Diameter
The Bach 11B has a cup diameter of 15.70 mm / 0.6181 in compared to 15.65 mm / 0.6161 in on the Bach 11½A — a difference of 0.05 mm / 0.0020 in. A wider cup generally produces a fuller, darker tone but requires more air support.
Cup Depth
The Bach 11½A has a very deep cup while the Bach 11B has a deep cup. Deeper cups favor a darker, richer sound; shallower cups provide more brightness and easier upper register.
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.