Bach 10½E vs Marcinkiewicz 2S
The Marcinkiewicz 2S has a wider cup diameter, the Marcinkiewicz 2S has a larger throat opening.
Cup Diameter
The Marcinkiewicz 2S has a cup diameter of 17.27 mm / 0.6799 in compared to 15.90 mm / 0.6260 in on the Bach 10½E — a difference of 1.37 mm / 0.0539 in. A wider cup generally produces a fuller, darker tone but requires more air support.
Cup Depth
Both mouthpieces share a shallow cup depth, so the sound character from depth alone will be very similar.
Throat Diameter
The Marcinkiewicz 2S has a wider throat (3.73 mm / 0.1469 in vs 3.66 mm / 0.1441 in). A wider throat allows more air through, increasing volume and projection but reducing resistance.
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.