Bach 1¼G vs Yamaha SL-YEO-S
The Yamaha SL-YEO-S has a wider cup diameter, the Bach 1¼G features a deeper cup, the Yamaha SL-YEO-S has a larger throat opening.
The internal diameter of the cup, measured at the widest point inside the rim.
Mouthpiece A
Bach 1¼G
• Trombone
Cup diameter27.50 mm / 1.0827 in
Best suited for
Orchestral playing — large cup for full, dark tone
High-volume projection — open throat for power
vs
Mouthpiece B
Yamaha SL-YEO-S
• Trombone
Cup diameter28.72 mm / 1.1307 in
Best suited for
Orchestral playing — large cup for full, dark tone
High-volume projection — open throat for power
Cup Diameter
The Yamaha SL-YEO-S has a cup diameter of 28.72 mm / 1.1307 in compared to 27.50 mm / 1.0827 in on the Bach 1¼G — a difference of 1.22 mm / 0.0480 in. A wider cup generally produces a fuller, darker tone but requires more air support.
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.