Bach 17C vs Yamaha AH-37C4
The Bach 17C has a wider cup diameter, the Yamaha AH-37C4 features a deeper cup, the Bach 17C has a larger throat opening.
The internal diameter of the cup, measured at the widest point inside the rim.
Mouthpiece A
Bach 17C
• Baritone / Euphonium
Cup diameter24.20 mm / 0.9528 in
Best suited for
High-volume projection — open throat for power
vs
Mouthpiece B
Yamaha AH-37C4
• Baritone / Euphonium
Cup diameter18.60 mm / 0.7323 in
Best suited for
High-volume projection — open throat for power
Cup Diameter
The Bach 17C has a cup diameter of 24.20 mm / 0.9528 in compared to 18.60 mm / 0.7323 in on the Yamaha AH-37C4 — a difference of 5.60 mm / 0.2205 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.