Bach 11C vs Bach 12
The Bach 11C has a wider cup diameter, the Bach 12 features a deeper cup.
Mouthpiece A
Bach 11C
• Baritone / Euphonium
Cup diameter24.70 mm / 0.9724 in
Cup depthShallow
Rim width—
Throat diameter5.85 mm / 0.2303 in
Backbore—
Finish—
Material—
Best suited for
High-volume projection — open throat for power
vs
Mouthpiece B
Bach 12
• Baritone / Euphonium
Cup diameter24.50 mm / 0.9646 in
Cup depthDeep
Rim width—
Throat diameter5.85 mm / 0.2303 in
Backbore—
Finish—
Material—
Best suited for
Orchestral playing — large cup for full, dark tone
High-volume projection — open throat for power
Cup Diameter
The Bach 11C has a cup diameter of 24.70 mm / 0.9724 in compared to 24.50 mm / 0.9646 in on the Bach 12 — 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
The Bach 12 has a deep cup while the Bach 11C has a shallow 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 5.85 mm / 0.2303 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.