Which has a bigger cup — Bach 17C or Kelly 5G-EU-SS?

The Kelly 5G-EU-SS has a cup diameter of 25.40 mm / 1.0000 in compared to 24.20 mm / 0.9528 in on the Bach 17C — a difference of 1.20 mm / 0.0472 in. A wider cup generally produces a fuller, darker tone but requires more air support.

How does cup depth compare between Bach 17C and Kelly 5G-EU-SS?

The Kelly 5G-EU-SS has a — cup while the Bach 17C has a shallow cup. Deeper cups favor a darker, richer sound; shallower cups provide more brightness and easier upper register.

Bach 17C vs Kelly 5G-EU-SS

Name: Kelly 5G-EU-SS
Brand: Kelly

The Kelly 5G-EU-SS has a wider cup diameter, the Kelly 5G-EU-SS features a deeper cup.

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

Base metal or construction (e.g. brass, stainless steel, plastic). Influences weight, response, and tone color.

Mouthpiece A

Bach 17C

• Baritone / Euphonium

Material—

Best suited for

📣High-volume projection — open throat for power

Mouthpiece B

Kelly 5G-EU-SS

• Baritone / Euphonium

General

Material316 Surgical Stainless Steel

Best suited for

🎻Orchestral playing — large cup for full, dark tone

📋Euphonium general use

Material

The Bach 17C is described as unspecified, and the Kelly 5G-EU-SS as 316 Surgical Stainless Steel. Material affects mass, warmth, and how quickly the piece responds.

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 17C details Kelly 5G-EU-SS details Bach 17C equivalents Kelly 5G-EU-SS equivalents

Bach 17C vs Kelly 5G-EU-SS

Material

Playing Characteristics

What Do These Model Names Mean?

What Changes If You Switch?

Which is better?

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