Which has a bigger cup — Bob Reeves RP4 or Yamaha TR-14B4?

The Yamaha TR-14B4 has a cup diameter of 16.85 mm / 0.6634 in compared to 16.27 mm / 0.6406 in on the Bob Reeves RP4 — a difference of 0.58 mm / 0.0228 in. A wider cup generally produces a fuller, darker tone but requires more air support.

How does cup depth compare between Bob Reeves RP4 and Yamaha TR-14B4?

Both mouthpieces share a shallow cup depth, so the sound character from depth alone will be very similar.

Bob Reeves RP4 vs Yamaha TR-14B4

Name: Yamaha TR-14B4
Brand: Yamaha

The Yamaha TR-14B4 has a wider cup diameter.

Overall Comparison Cup Diameter Cup Depth Rim Width Throat Diameter Backbore Finish Material

The narrowest point at the bottom of the cup. Affects resistance, volume, and tone color.

Mouthpiece A

Bob Reeves RP4

• Trumpet

Throat diameter—

Mouthpiece B

Yamaha TR-14B4

• Trumpet

Throat diameter3.65 mm / 0.1437 in

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.