Bach 5MV vs Marcinkiewicz 12
The Marcinkiewicz 12 has a wider cup diameter, the Bach 5MV has a larger throat opening.
The internal diameter of the cup, measured at the widest point inside the rim.
Mouthpiece A
Bach 5MV
• Cornet
Cup diameter16.25 mm / 0.6398 in
Best suited for
High-volume projection — open throat for power
vs
Mouthpiece B
Marcinkiewicz 12
• Cornet
Cup diameter16.31 mm / 0.6421 in
Cup Diameter
The Marcinkiewicz 12 has a cup diameter of 16.31 mm / 0.6421 in compared to 16.25 mm / 0.6398 in on the Bach 5MV — a difference of 0.06 mm / 0.0024 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.