Bach 1½G vs Bach 1½GM
the Bach 1½GM has a larger throat opening.
The narrowest point at the bottom of the cup. Affects resistance, volume, and tone color.
Mouthpiece A
Bach 1½G
• Trombone
Throat diameter7.01 mm / 0.2760 in
Best suited for
Orchestral playing — large cup for full, dark tone
High-volume projection — open throat for power
vs
Mouthpiece B
Bach 1½GM
• Trombone
Throat diameter8.10 mm / 0.3189 in
Best suited for
Orchestral playing — large cup for full, dark tone
High-volume projection — open throat for power
Throat Diameter
The Bach 1½GM has a wider throat (8.10 mm / 0.3189 in vs 7.01 mm / 0.2760 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.