Bach 10½D vs Bach 8½A
The Bach 8½A has a wider cup diameter, the Bach 8½A features a deeper cup.
Mouthpiece A
Bach 10½D
• Cornet
Cup diameter15.90 mm
Cup depthShallow
Rim width—
Throat diameter3.66 mm
Backbore—
Finish—
Material—
Best suited for
Lead / commercial — shallow cup for brightness and range
vs
Mouthpiece B
Bach 8½A
• Cornet
Cup diameter16.10 mm
Cup depthVery deep
Rim width—
Throat diameter3.66 mm
Backbore—
Finish—
Material—
Cup Diameter
The Bach 8½A has a cup diameter of 16.10 mm compared to 15.90 mm on the Bach 10½D — a difference of +0.20 mm. A wider cup generally produces a fuller, darker tone but requires more air support.
Cup Depth
The Bach 8½A has a very deep cup while the Bach 10½D has a shallow 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 3.66 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.