Bach 5GB (small shank) vs Yamaha AH-38D4
The Bach 5GB (small shank) has a wider cup diameter, the Bach 5GB (small shank) features a deeper cup, the Bach 5GB (small shank) has a larger throat opening.
The internal diameter of the cup, measured at the widest point inside the rim.
Mouthpiece A
Bach 5GB (small shank)
• Baritone / Euphonium
Cup diameter25.50 mm / 1.0039 in
Best suited for
Orchestral playing — large cup for full, dark tone
High-volume projection — open throat for power
vs
Mouthpiece B
Yamaha AH-38D4
• Baritone / Euphonium
Cup diameter18.90 mm / 0.7441 in
Best suited for
Orchestral playing — large cup for full, dark tone
High-volume projection — open throat for power
Cup Diameter
The Bach 5GB (small shank) has a cup diameter of 25.50 mm / 1.0039 in compared to 18.90 mm / 0.7441 in on the Yamaha AH-38D4 — a difference of 6.60 mm / 0.2598 in. 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.