Marcinkiewicz 11 vs Schilke 45B
The Marcinkiewicz 11 has a wider cup diameter, the Marcinkiewicz 11 features a deeper cup.
Cup Diameter
The Marcinkiewicz 11 has a cup diameter of 25.40 mm / 1.0000 in compared to 24.30 mm / 0.9567 in on the Schilke 45B — a difference of 1.10 mm / 0.0433 in. A wider cup generally produces a fuller, darker tone but requires more air support.
Cup Depth
The Marcinkiewicz 11 has a deep cup while the Schilke 45B has a medium cup. Deeper cups favor a darker, richer sound; shallower cups provide more brightness and easier upper register.
Throat Diameter
Throat diameters are essentially identical at 5.94 mm / 0.2339 in, so resistance feel will be comparable.
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.