Bach 2¾C vs Yamaha CR-11C4S
The Yamaha CR-11C4S has a wider cup diameter, the Bach 2¾C has a larger throat opening.
Cup Diameter
The Yamaha CR-11C4S has a cup diameter of 16.46 mm / 0.6480 in compared to 16.40 mm / 0.6457 in on the Bach 2¾C — a difference of 0.06 mm / 0.0024 in. A wider cup generally produces a fuller, darker tone but requires more air support.
Cup Depth
Both mouthpieces share a medium cup depth, so the sound character from depth alone will be very similar.
Throat Diameter
The Bach 2¾C 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.