Bach 1B vs Bach 6B
The Bach 1B has a wider cup diameter.
The internal diameter of the cup, measured at the widest point inside the rim.
Mouthpiece A
Bach 1B
• Cornet
Cup diameter17.00 mm / 0.6693 in
Best suited for
Orchestral playing — large cup for full, dark tone
vs
Mouthpiece B
Bach 6B
• Cornet
Cup diameter16.20 mm / 0.6378 in
Cup Diameter
The Bach 1B has a cup diameter of 17.00 mm / 0.6693 in compared to 16.20 mm / 0.6378 in on the Bach 6B — a difference of 0.80 mm / 0.0315 in. 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.