Bach 8½A vs Denis Wick 5
The Bach 8½A has a wider cup diameter, the Denis Wick 5 has a larger throat opening.
Cup Diameter
The Bach 8½A has a cup diameter of 16.10 mm / 0.6339 in compared to 16.00 mm / 0.6299 in on the Denis Wick 5 — a difference of 0.10 mm / 0.0039 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 Denis Wick 5 has a wider throat (4.45 mm / 0.1752 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.