Bruno Tilz 306-5 GS vs Marcinkiewicz ET3C. Loper
The Bruno Tilz 306-5 GS has a wider cup diameter, the Marcinkiewicz ET3C. Loper features a deeper cup, the Bruno Tilz 306-5 GS has a larger throat opening.
Cup Diameter
The Bruno Tilz 306-5 GS has a cup diameter of 26.00 mm / 1.0236 in compared to 25.10 mm / 0.9882 in on the Marcinkiewicz ET3C. Loper — a difference of 0.90 mm / 0.0354 in. A wider cup generally produces a fuller, darker tone but requires more air support.
Cup Depth
The Marcinkiewicz ET3C. Loper has a deep cup while the Bruno Tilz 306-5 GS has a medium cup. Deeper cups favor a darker, richer sound; shallower cups provide more brightness and easier upper register.
Throat Diameter
The Bruno Tilz 306-5 GS has a wider throat (6.80 mm / 0.2677 in vs 5.94 mm / 0.2339 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.