Conn Imp. Precision 3 vs Kelly 7C
The Kelly 7C has a wider cup diameter.
The internal diameter of the cup, measured at the widest point inside the rim.
Mouthpiece A
Conn Imp. Precision 3
• Cornet
GeneralCup diameter16.41 mm / 0.6461 in
Best suited for
All-round versatile — balanced cup for general playing
Most popular model; all-around
Bright quality of tone in all registers
vs
Mouthpiece B
Kelly 7C
• Cornet
GeneralCup diameter16.51 mm / 0.6500 in
Best suited for
All-round versatile — balanced cup for general playing
Beginner / intermediate
Cup Diameter
The Kelly 7C has a cup diameter of 16.51 mm / 0.6500 in compared to 16.41 mm / 0.6461 in on the Conn Imp. Precision 3 — a difference of 0.10 mm / 0.0039 in. A wider cup generally produces a fuller, darker tone but requires more air support.
Which is better?
Both mouthpieces are categorized as "General" — the physical dimensions above will determine which suits your embouchure and playing style better.