Denis Wick 3 vs Marcinkiewicz 315
The Marcinkiewicz 315 has a wider cup diameter, the Denis Wick 3 has a larger throat opening.
Cup Diameter
The Marcinkiewicz 315 has a cup diameter of 17.20 mm / 0.6772 in compared to 16.75 mm / 0.6594 in on the Denis Wick 3 — a difference of 0.45 mm / 0.0177 in. A wider cup generally produces a fuller, darker tone but requires more air support.
Cup Depth
Both mouthpieces share a very deep cup depth, so the sound character from depth alone will be very similar.
Throat Diameter
The Denis Wick 3 has a wider throat (4.57 mm / 0.1799 in vs 3.73 mm / 0.1469 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.