Bach 18 vs Marcinkiewicz CH EF 21J. Cox
The Marcinkiewicz CH EF 21J. Cox has a wider cup diameter, the Marcinkiewicz CH EF 21J. Cox features a deeper cup, the Marcinkiewicz CH EF 21J. Cox has a larger throat opening.
The internal diameter of the cup, measured at the widest point inside the rim.
Mouthpiece A
Bach 18
• French Horn
Cup diameter16.15 mm / 0.6358 in
Best suited for
All-round versatile — balanced cup for general playing
High-volume projection — open throat for power
vs
Mouthpiece B
Marcinkiewicz CH EF 21J. Cox
• French Horn
Cup diameter17.48 mm / 0.6882 in
Best suited for
Orchestral playing — large cup for full, dark tone
High-volume projection — open throat for power
Cup Diameter
The Marcinkiewicz CH EF 21J. Cox has a cup diameter of 17.48 mm / 0.6882 in compared to 16.15 mm / 0.6358 in on the Bach 18 — a difference of 1.33 mm / 0.0524 in. A wider cup generally produces a fuller, darker tone but requires more air support.
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.