Yamaha HR-31B vs Yamaha HR-32B
The Yamaha HR-32B has a wider cup diameter.
Mouthpiece A
Yamaha HR-31B
• French Horn
Cup diameter17.47 mm / 0.6878 in
Cup depthShallow
Rim width—
Throat diameter3.90 mm / 0.1535 in
BackboreSemi-wide
Finish—
Material—
Best suited for
High-volume projection — open throat for power
vs
Mouthpiece B
Yamaha HR-32B
• French Horn
Cup diameter17.67 mm / 0.6957 in
Cup depthShallow
Rim width—
Throat diameter3.90 mm / 0.1535 in
BackboreSemi-wide
Finish—
Material—
Best suited for
High-volume projection — open throat for power
Cup Diameter
The Yamaha HR-32B has a cup diameter of 17.67 mm / 0.6957 in compared to 17.47 mm / 0.6878 in on the Yamaha HR-31B — a difference of 0.20 mm / 0.0079 in. A wider cup generally produces a fuller, darker tone but requires more air support.
Cup Depth
Both mouthpieces share a shallow cup depth, so the sound character from depth alone will be very similar.
Throat Diameter
Throat diameters are essentially identical at 3.90 mm / 0.1535 in, so resistance feel will be comparable.
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.