Bach 3C vs Bach 5B
The Bach 3C has a wider cup diameter, the Bach 5B features a deeper cup.
Mouthpiece A
Bach 3C
• Trumpet
Cup diameter16.30 mm / 0.6417 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 5B
• Trumpet
Cup diameter16.25 mm / 0.6398 in
Cup depthDeep
Rim width—
Throat diameter3.66 mm / 0.1441 in
Backbore—
Finish—
Material—
Cup Diameter
The Bach 3C has a cup diameter of 16.30 mm / 0.6417 in compared to 16.25 mm / 0.6398 in on the Bach 5B — 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 5B has a deep cup while the Bach 3C has a medium 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.