Bach 1¼C vs Yamaha TR-14C4
The Bach 1¼C has a wider cup diameter, the Bach 1¼C has a larger throat opening.
Cup Diameter
The Bach 1¼C has a cup diameter of 17.00 mm / 0.6693 in compared to 16.88 mm / 0.6646 in on the Yamaha TR-14C4 — a difference of 0.12 mm / 0.0047 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 1¼C 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.