Bach 18D vs Bach 8
The Bach 8 has a wider cup diameter, the Bach 8 features a deeper cup.
The internal diameter of the cup, measured at the widest point inside the rim.
Mouthpiece A
Bach 18D
• Baritone / Euphonium
Cup diameter24.20 mm
Best suited for
High-volume projection — open throat for power
vs
Mouthpiece B
Bach 8
• Baritone / Euphonium
Cup diameter24.75 mm
Best suited for
High-volume projection — open throat for power
Cup Diameter
The Bach 8 has a cup diameter of 24.75 mm compared to 24.20 mm on the Bach 18D — a difference of +0.55 mm. A wider cup generally produces a fuller, darker tone but requires more air support.
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.