Giardinelli C12 vs Marcinkiewicz 7
The Marcinkiewicz 7 has a wider cup diameter, the Marcinkiewicz 7 has a larger throat opening.
Cup Diameter
The Marcinkiewicz 7 has a cup diameter of 17.75 mm / 0.6988 in compared to 17.50 mm / 0.6890 in on the Giardinelli C12 — a difference of 0.25 mm / 0.0098 in. A wider cup generally produces a fuller, darker tone but requires more air support.
Cup Depth
Both mouthpieces share a medium cup depth, so the sound character from depth alone will be very similar.
Throat Diameter
The Marcinkiewicz 7 has a wider throat (5.11 mm / 0.2012 in vs 4.80 mm / 0.1890 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.