Bach 5GS (large shank) vs Giardinelli Sym. T
The Giardinelli Sym. T has a wider cup diameter, the Bach 5GS (large shank) has a larger throat opening.
Cup Diameter
The Giardinelli Sym. T has a cup diameter of 25.80 mm / 1.0157 in compared to 25.50 mm / 1.0039 in on the Bach 5GS (large shank) — a difference of 0.30 mm / 0.0118 in. A wider cup generally produces a fuller, darker tone but requires more air support.
Cup Depth
Both mouthpieces share a deep cup depth, so the sound character from depth alone will be very similar.
Throat Diameter
The Bach 5GS (large shank) has a wider throat (6.63 mm / 0.2610 in vs 6.40 mm / 0.2520 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.