Bach 8½A vs Curry 10.5 BBC
The Bach 8½A has a wider cup diameter, the Curry 10.5 BBC has a larger throat opening.
Cup Diameter
The Bach 8½A has a cup diameter of 16.10 mm / 0.6339 in compared to 15.88 mm / 0.6250 in on the Curry 10.5 BBC — a difference of 0.23 mm / 0.0089 in. A wider cup generally produces a fuller, darker tone but requires more air support.
Cup Depth
Both mouthpieces share a very deep cup depth, so the sound character from depth alone will be very similar.
Throat Diameter
The Curry 10.5 BBC has a wider throat (4.06 mm / 0.1600 in vs 3.66 mm / 0.1441 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.