Bach 18 vs Bach 24AW
The Bach 18 has a wider cup diameter, the Bach 24AW features a deeper cup.
Mouthpiece A
Bach 18
• Tuba
Cup diameter32.10 mm / 1.2638 in
Cup depthMedium
Rim width—
Throat diameter9.00 mm / 0.3543 in
Backbore—
Finish—
Material—
Best suited for
High-volume projection — open throat for power
vs
Mouthpiece B
Bach 24AW
• Tuba
Cup diameter31.25 mm / 1.2303 in
Cup depthVery deep
Rim width—
Throat diameter9.00 mm / 0.3543 in
Backbore—
Finish—
Material—
Best suited for
Orchestral playing — large cup for full, dark tone
High-volume projection — open throat for power
Cup Diameter
The Bach 18 has a cup diameter of 32.10 mm / 1.2638 in compared to 31.25 mm / 1.2303 in on the Bach 24AW — a difference of 0.85 mm / 0.0335 in. A wider cup generally produces a fuller, darker tone but requires more air support.
Cup Depth
The Bach 24AW has a very deep cup while the Bach 18 has a medium cup. Deeper cups favor a darker, richer sound; shallower cups provide more brightness and easier upper register.
Throat Diameter
Throat diameters are essentially identical at 9.00 mm / 0.3543 in, so resistance feel will be comparable.
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.