Bach 2½C vs Conn Connstellation 5CW
The Conn Connstellation 5CW has a wider cup diameter, the Conn Connstellation 5CW features a deeper cup.
Cup Diameter
The Conn Connstellation 5CW has a cup diameter of 16.76 mm / 0.6598 in compared to 16.40 mm / 0.6457 in on the Bach 2½C — a difference of 0.36 mm / 0.0142 in. A wider cup generally produces a fuller, darker tone but requires more air support.
Cup Depth
The Conn Connstellation 5CW has a — cup while the Bach 2½C has a medium cup. Deeper cups favor a darker, richer sound; shallower cups provide more brightness and easier upper register.
Material
The Bach 2½C is described as unspecified, and the Conn Connstellation 5CW 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.