Bach 12E vs Marcinkiewicz 5F
The Marcinkiewicz 5F has a wider cup diameter, the Bach 12E features a deeper cup, the Marcinkiewicz 5F has a larger throat opening.
Cup Diameter
The Marcinkiewicz 5F has a cup diameter of 25.78 mm / 1.0150 in compared to 24.50 mm / 0.9646 in on the Bach 12E — a difference of 1.28 mm / 0.0504 in. A wider cup generally produces a fuller, darker tone but requires more air support.
Cup Depth
The Bach 12E has a shallow cup while the Marcinkiewicz 5F has a very shallow cup. Deeper cups favor a darker, richer sound; shallower cups provide more brightness and easier upper register.
Throat Diameter
The Marcinkiewicz 5F has a wider throat (6.53 mm / 0.2571 in vs 5.85 mm / 0.2303 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.