Marcinkiewicz CH 5S vs Marcinkiewicz 3
The Marcinkiewicz 3 has a wider cup diameter, the Marcinkiewicz 3 has a larger throat opening.
Cup Diameter
The Marcinkiewicz 3 has a cup diameter of 17.91 mm / 0.7051 in compared to 17.75 mm / 0.6988 in on the Marcinkiewicz CH 5S — a difference of 0.16 mm / 0.0063 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 3 has a wider throat (5.41 mm / 0.2130 in vs 5.23 mm / 0.2059 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.