GR Technologies 66.6M2** vs Schilke 13A4a
The GR Technologies 66.6M2** has a wider cup diameter, the GR Technologies 66.6M2** features a deeper cup.
Mouthpiece A
GR Technologies 66.6M2**
• Trumpet
Cup diameter16.92 mm / 0.6661 in
Cup depthDeep
Rim width—
Throat diameter—
Backbore—
Finish—
Material—
Best suited for
Orchestral playing — large cup for full, dark tone
vs
Mouthpiece B
Schilke 13A4a
• Trumpet
Cup diameter16.76 mm / 0.6598 in
Cup depthShallow
Rim width—
Throat diameter3.66 mm / 0.1441 in
Backbore27
Finish—
Material—
Cup Diameter
The GR Technologies 66.6M2** has a cup diameter of 16.92 mm / 0.6661 in compared to 16.76 mm / 0.6598 in on the Schilke 13A4a — a difference of 0.16 mm / 0.0063 in. A wider cup generally produces a fuller, darker tone but requires more air support.
Cup Depth
The GR Technologies 66.6M2** has a deep cup while the Schilke 13A4a has a shallow 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.