Bob Reeves RP8 vs Yamaha TR-14B4
The Yamaha TR-14B4 has a wider cup diameter, the Bob Reeves RP8 features a deeper cup.
Mouthpiece A
Bob Reeves RP8
• Trumpet
Cup diameter16.67 mm / 0.6563 in
Cup depthMedium
Rim width—
Throat diameter—
Backbore—
Finish—
Material—
Best suited for
All-round versatile — balanced cup for general playing
vs
Mouthpiece B
Yamaha TR-14B4
• Trumpet
Cup diameter16.85 mm / 0.6634 in
Cup depthShallow
Rim width—
Throat diameter3.65 mm / 0.1437 in
BackboreSemi-narrow
Finish—
Material—
Cup Diameter
The Yamaha TR-14B4 has a cup diameter of 16.85 mm / 0.6634 in compared to 16.67 mm / 0.6563 in on the Bob Reeves RP8 — a difference of 0.18 mm / 0.0071 in. A wider cup generally produces a fuller, darker tone but requires more air support.
Cup Depth
The Bob Reeves RP8 has a medium cup while the Yamaha TR-14B4 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.