Bach 8½A vs Conn Precision 1
The Conn Precision 1 has a wider cup diameter, the Conn Precision 1 features a deeper cup.
Cup Diameter
The Conn Precision 1 has a cup diameter of 16.56 mm / 0.6520 in compared to 16.10 mm / 0.6339 in on the Bach 8½A — a difference of 0.46 mm / 0.0181 in. A wider cup generally produces a fuller, darker tone but requires more air support.
Cup Depth
The Conn Precision 1 has a — cup while the Bach 8½A has a very deep cup. Deeper cups favor a darker, richer sound; shallower cups provide more brightness and easier upper register.
Material
The Bach 8½A is described as unspecified, and the Conn Precision 1 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.