Which has a bigger cup — Bob Reeves RP5 or GR Technologies 65SZ?

The GR Technologies 65SZ has a cup diameter of 16.50 mm / 0.6496 in compared to 16.47 mm / 0.6484 in on the Bob Reeves RP5 — a difference of 0.03 mm / 0.0012 in. A wider cup generally produces a fuller, darker tone but requires more air support.

How does cup depth compare between Bob Reeves RP5 and GR Technologies 65SZ?

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

Bob Reeves RP5 vs GR Technologies 65SZ

Name: GR Technologies 65SZ
Brand: GR Technologies

The GR Technologies 65SZ has a wider cup diameter.

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

The width of the rim surface that contacts the lips. Wider rims improve endurance; narrower rims improve flexibility.

Mouthpiece A

Bob Reeves RP5

• Trumpet

Rim width—

Mouthpiece B

GR Technologies 65SZ

• Trumpet

Rim width—

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.