Which has a bigger cup — Yamaha HR-30B or Yamaha HR-31B?

The Yamaha HR-31B has a cup diameter of 17.47 mm / 0.6878 in compared to 17.27 mm / 0.6799 in on the Yamaha HR-30B — a difference of 0.20 mm / 0.0079 in. A wider cup generally produces a fuller, darker tone but requires more air support.

How does cup depth compare between Yamaha HR-30B and Yamaha HR-31B?

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

Yamaha HR-30B vs Yamaha HR-31B

Name: Yamaha HR-31B
Brand: Yamaha

The Yamaha HR-31B 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

Yamaha HR-30B

• French Horn

Rim width—

Best suited for

📣High-volume projection — open throat for power

Mouthpiece B

Yamaha HR-31B

• French Horn

Rim width—

Best suited for

📣High-volume projection — open throat for power

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.