Bach 2½C vs Yamaha CR-11A4L
The Bach 2½C has a wider cup diameter, the Bach 2½C features a deeper cup, the Bach 2½C has a larger throat opening.
Cup Diameter
The Bach 2½C has a cup diameter of 16.40 mm / 0.6457 in compared to 15.99 mm / 0.6295 in on the Yamaha CR-11A4L — a difference of 0.41 mm / 0.0161 in. A wider cup generally produces a fuller, darker tone but requires more air support.
Cup Depth
The Bach 2½C has a medium cup while the Yamaha CR-11A4L has a very shallow cup. Deeper cups favor a darker, richer sound; shallower cups provide more brightness and easier upper register.
Throat Diameter
The Bach 2½C has a wider throat (3.66 mm / 0.1441 in vs 3.65 mm / 0.1437 in). A wider throat allows more air through, increasing volume and projection but reducing resistance.
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.