Bach 1¼C vs Conn Imp. Precision 6
The Bach 1¼C has a wider cup diameter, the Bach 1¼C features a deeper cup.
Cup Diameter
The Bach 1¼C has a cup diameter of 17.00 mm / 0.6693 in compared to 16.41 mm / 0.6461 in on the Conn Imp. Precision 6 — a difference of 0.59 mm / 0.0232 in. A wider cup generally produces a fuller, darker tone but requires more air support.
Cup Depth
The Bach 1¼C has a medium cup while the Conn Imp. Precision 6 has a shallow cup. Deeper cups favor a darker, richer sound; shallower cups provide more brightness and easier upper register.
Material
The Bach 1¼C is described as unspecified, and the Conn Imp. Precision 6 as Silver-plated brass. Material affects mass, warmth, and how quickly the piece responds.
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.