Kelly 31 vs Kelly MC
The Kelly 31 has a wider cup diameter, the Kelly 31 features a deeper cup.
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
Kelly MC
• French Horn
GeneralThroat diameter3.80 mm / 0.1496 in
Best suited for
High-volume projection — open throat for power
All-purpose French horn
Throat Diameter
Throat diameters are essentially identical at 3.80 mm / 0.1496 in, so resistance feel will be comparable.
Which is better?
Both mouthpieces are categorized as "General" — the physical dimensions above will determine which suits your embouchure and playing style better.