GR Technologies 66M vs Marcinkiewicz E18E. Miyashiro
The GR Technologies 66M has a wider cup diameter, the Marcinkiewicz E18E. Miyashiro features a deeper cup.
Mouthpiece A
GR Technologies 66M
• Trumpet
Cup diameter16.76 mm / 0.6598 in
Cup depthMedium
Rim width—
Throat diameter—
Backbore—
Finish—
Material—
vs
Mouthpiece B
Marcinkiewicz E18E. Miyashiro
• Trumpet
Cup diameter16.38 mm / 0.6449 in
Cup depthVery deep
Rim width—
Throat diameter3.73 mm / 0.1469 in
Backbore—
Finish—
Material—
Cup Diameter
The GR Technologies 66M has a cup diameter of 16.76 mm / 0.6598 in compared to 16.38 mm / 0.6449 in on the Marcinkiewicz E18E. Miyashiro — a difference of 0.38 mm / 0.0150 in. A wider cup generally produces a fuller, darker tone but requires more air support.
Cup Depth
The Marcinkiewicz E18E. Miyashiro has a very deep cup while the GR Technologies 66M has a medium cup. Deeper cups favor a darker, richer sound; shallower cups provide more brightness and easier upper register.
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.