GR Technologies 64FD vs GR Technologies E65FD
The GR Technologies E65FD has a wider cup diameter.
Mouthpiece A
GR Technologies 64FD
• Flugelhorn
Cup diameter16.26 mm / 0.6402 in
Cup depthDeep
Rim width—
Throat diameter—
Backbore—
Finish—
Material—
vs
Mouthpiece B
GR Technologies E65FD
• Flugelhorn
Cup diameter16.50 mm / 0.6496 in
Cup depthDeep
Rim width—
Throat diameter—
Backbore—
Finish—
Material—
Cup Diameter
The GR Technologies E65FD has a cup diameter of 16.50 mm / 0.6496 in compared to 16.26 mm / 0.6402 in on the GR Technologies 64FD — a difference of 0.24 mm / 0.0094 in. A wider cup generally produces a fuller, darker tone but requires more air support.
Cup Depth
Both mouthpieces share a deep cup depth, so the sound character from depth alone will be very similar.
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.