Bach 5C vs GR Technologies X66.8 C*
The GR Technologies X66.8 C* has a wider cup diameter, the GR Technologies X66.8 C* features a deeper cup.
Mouthpiece A
Bach 5C
• Trumpet
Cup diameter16.25 mm / 0.6398 in
Cup depthMedium
Rim width—
Throat diameter3.66 mm / 0.1441 in
Backbore—
Finish—
Material—
Best suited for
All-round versatile — balanced cup for general playing
vs
Mouthpiece B
GR Technologies X66.8 C*
• Trumpet
Cup diameter16.97 mm / 0.6681 in
Cup depthDeep
Rim width—
Throat diameter—
Backbore—
Finish—
Material—
Best suited for
Orchestral playing — large cup for full, dark tone
Cup Diameter
The GR Technologies X66.8 C* has a cup diameter of 16.97 mm / 0.6681 in compared to 16.25 mm / 0.6398 in on the Bach 5C — a difference of 0.72 mm / 0.0283 in. A wider cup generally produces a fuller, darker tone but requires more air support.
Cup Depth
The GR Technologies X66.8 C* has a deep cup while the Bach 5C 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.