Bach 18 vs Yamaha HR-29C4
The Yamaha HR-29C4 has a wider cup diameter, the Bach 18 has a larger throat opening.
Mouthpiece A
Bach 18
• French Horn
Cup diameter16.15 mm
Cup depthMedium
Rim width—
Throat diameter4.50 mm
Backbore—
Finish—
Material—
Best suited for
All-round versatile — balanced cup for general playing
High-volume projection — open throat for power
vs
Mouthpiece B
Yamaha HR-29C4
• French Horn
Cup diameter17.08 mm
Cup depthMedium
Rim width—
Throat diameter3.98 mm
BackboreStandard
Finish—
Material—
Best suited for
High-volume projection — open throat for power
Cup Diameter
The Yamaha HR-29C4 has a cup diameter of 17.08 mm compared to 16.15 mm on the Bach 18 — a difference of +0.93 mm. 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
The Bach 18 has a wider throat (4.50 mm vs 3.98 mm). A wider throat allows more air through, increasing volume and projection but reducing resistance.
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.