Kelly 31 vs Yamaha HR-35C4
The Yamaha HR-35C4 has a wider cup diameter, the Kelly 31 features a deeper cup, the Yamaha HR-35C4 has a larger throat opening.
The narrowest point at the bottom of the cup. Affects resistance, volume, and tone color.
Mouthpiece A
Kelly 31
• French Horn
GeneralThroat diameter3.80 mm / 0.1496 in
Best suited for
Orchestral playing — large cup for full, dark tone
High-volume projection — open throat for power
French horn deep cup
vs
Mouthpiece B
Yamaha HR-35C4
• French Horn
Throat diameter3.98 mm / 0.1567 in
Best suited for
High-volume projection — open throat for power
Throat Diameter
The Yamaha HR-35C4 has a wider throat (3.98 mm / 0.1567 in vs 3.80 mm / 0.1496 in). A wider throat allows more air through, increasing volume and projection but reducing resistance.
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.