Bach 8½A vs Conn Connstellation 9CW
The Bach 8½A has a wider cup diameter, the Conn Connstellation 9CW features a deeper cup.
Cup Diameter
The Bach 8½A has a cup diameter of 16.10 mm / 0.6339 in compared to 15.88 mm / 0.6252 in on the Conn Connstellation 9CW — a difference of 0.22 mm / 0.0087 in. A wider cup generally produces a fuller, darker tone but requires more air support.
Cup Depth
The Conn Connstellation 9CW 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 Connstellation 9CW 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.