Yamaha HR-31-GP vs Yamaha HR-32-GP
The Yamaha HR-32-GP has a wider cup diameter.
Mouthpiece A
Yamaha HR-31-GP
• French Horn
Cup diameter17.28 mm / 0.6803 in
Cup depthMedium
Rim width—
Throat diameter4.40 mm / 0.1732 in
BackboreSemi-narrow
Finish—
Material—
Best suited for
High-volume projection — open throat for power
vs
Mouthpiece B
Yamaha HR-32-GP
• French Horn
Cup diameter17.48 mm / 0.6882 in
Cup depthMedium
Rim width—
Throat diameter4.40 mm / 0.1732 in
BackboreSemi-narrow
Finish—
Material—
Best suited for
High-volume projection — open throat for power
Cup Diameter
The Yamaha HR-32-GP has a cup diameter of 17.48 mm / 0.6882 in compared to 17.28 mm / 0.6803 in on the Yamaha HR-31-GP — 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 medium cup depth, so the sound character from depth alone will be very similar.
Throat Diameter
Throat diameters are essentially identical at 4.40 mm / 0.1732 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.