Bach 11 vs Kelly 31
The Kelly 31 has a wider cup diameter, the Kelly 31 features a deeper cup, the Bach 11 has a larger throat opening.
The narrowest point at the bottom of the cup. Affects resistance, volume, and tone color.
Mouthpiece A
Bach 11
• French Horn
Throat diameter4.50 mm / 0.1772 in
Best suited for
All-round versatile — balanced cup for general playing
High-volume projection — open throat for power
vs
Mouthpiece B
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
Throat Diameter
The Bach 11 has a wider throat (4.50 mm / 0.1772 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.