Bach 16 vs Yamaha HR-31D4
The Yamaha HR-31D4 has a wider cup diameter, the Bach 16 features a deeper cup.
Mouthpiece A
Bach 16
• French Horn
Cup diameter16.25 mm
Cup depthVery deep
Rim width—
Throat diameter4.50 mm
Backbore—
Finish—
Material—
Best suited for
High-volume projection — open throat for power
vs
Mouthpiece B
Yamaha HR-31D4
• French Horn
Cup diameter17.28 mm
Cup depthDeep
Rim width—
Throat diameter4.50 mm
BackboreSemi-narrow
Finish—
Material—
Best suited for
Orchestral playing — large cup for full, dark tone
High-volume projection — open throat for power
Cup Diameter
The Yamaha HR-31D4 has a cup diameter of 17.28 mm compared to 16.25 mm on the Bach 16 — a difference of +1.03 mm. A wider cup generally produces a fuller, darker tone but requires more air support.
Cup Depth
The Bach 16 has a very deep cup while the Yamaha HR-31D4 has a deep cup. Deeper cups favor a darker, richer sound; shallower cups provide more brightness and easier upper register.
Throat Diameter
Throat diameters are essentially identical at 4.50 mm, 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.