Bach 12C vs Bach 5G (small shank)
The Bach 5G (small shank) has a wider cup diameter, the Bach 5G (small shank) features a deeper cup, the Bach 5G (small shank) has a larger throat opening.
The internal diameter of the cup, measured at the widest point inside the rim.
Mouthpiece A
Bach 12C
• Baritone / Euphonium
Cup diameter24.50 mm
Best suited for
High-volume projection — open throat for power
vs
Mouthpiece B
Bach 5G (small shank)
• Baritone / Euphonium
Cup diameter25.50 mm
Best suited for
Orchestral playing — large cup for full, dark tone
High-volume projection — open throat for power
Cup Diameter
The Bach 5G (small shank) has a cup diameter of 25.50 mm compared to 24.50 mm on the Bach 12C — a difference of +1.00 mm. 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.