Which has a bigger cup — Bach 15EW or Bach 18D?

The Bach 15EW has a cup diameter of 24.30 mm / 0.9567 in compared to 24.20 mm / 0.9528 in on the Bach 18D — a difference of 0.10 mm / 0.0039 in. A wider cup generally produces a fuller, darker tone but requires more air support.

Bach 15EW vs Bach 18D

Name: Bach 18D
Brand: Bach

The Bach 15EW has a wider cup diameter.

Overall Comparison Cup Diameter Cup Depth Rim Width Throat Diameter Backbore Finish Material

How deep the cup is, from shallow (brighter, easier high register) to deep (darker, fuller sound).

Mouthpiece A

Bach 15EW

• Trombone

Cup depthShallow

Best suited for

📣High-volume projection — open throat for power

Mouthpiece B

Bach 18D

• Trombone

Cup depthShallow

Best suited for

📣High-volume projection — open throat for power

Cup Depth

Both mouthpieces share a shallow cup depth, so the sound character from depth alone will be very similar.

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.

Open in interactive tool + Add third mouthpiece Bach 15EW details Bach 18D details Bach 15EW equivalents Bach 18D equivalents

Bach 15EW vs Bach 18D

Cup Depth

Playing Characteristics

What Do These Model Names Mean?

What Changes If You Switch?

Which is better?

Compare Bach 15EW with others

Compare Bach 18D with others

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