Bob Reeves 5G Gladstone vs Yamaha SL-48S-GP
The Bob Reeves 5G Gladstone has a wider cup diameter, the Bob Reeves 5G Gladstone features a deeper cup.
Mouthpiece A
Bob Reeves 5G Gladstone
• Trombone
Cup diameter25.55 mm / 1.0059 in
Cup depthDeep
Rim width—
Throat diameter—
Backbore—
Finish—
Material—
Best suited for
Orchestral playing — large cup for full, dark tone
vs
Mouthpiece B
Yamaha SL-48S-GP
• Trombone
Cup diameter25.25 mm / 0.9941 in
Cup depthMedium
Rim width—
Throat diameter6.62 mm / 0.2606 in
BackboreSemi-wide
Finish—
Material—
Best suited for
High-volume projection — open throat for power
Cup Diameter
The Bob Reeves 5G Gladstone has a cup diameter of 25.55 mm / 1.0059 in compared to 25.25 mm / 0.9941 in on the Yamaha SL-48S-GP — a difference of 0.30 mm / 0.0118 in. A wider cup generally produces a fuller, darker tone but requires more air support.
Cup Depth
The Bob Reeves 5G Gladstone has a deep cup while the Yamaha SL-48S-GP 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.