Marcinkiewicz 300 vs Marcinkiewicz 305
The Marcinkiewicz 300 has a wider cup diameter, the Marcinkiewicz 305 features a deeper cup.
The internal diameter of the cup, measured at the widest point inside the rim.
Mouthpiece A
Marcinkiewicz 300
• Cornet
Cup diameter17.58 mm / 0.6921 in
vs
Mouthpiece B
Marcinkiewicz 305
• Cornet
Cup diameter17.20 mm / 0.6772 in
Cup Diameter
The Marcinkiewicz 300 has a cup diameter of 17.58 mm / 0.6921 in compared to 17.20 mm / 0.6772 in on the Marcinkiewicz 305 — a difference of 0.38 mm / 0.0150 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.