Which has a bigger cup — Bach 1¼G or Kelly SKY-SS?

The Bach 1¼G has a cup diameter of 27.50 mm / 1.0827 in compared to 24.64 mm / 0.9701 in on the Kelly SKY-SS — a difference of 2.86 mm / 0.1126 in. A wider cup generally produces a fuller, darker tone but requires more air support.

How does cup depth compare between Bach 1¼G and Kelly SKY-SS?

The Bach 1¼G has a very deep cup while the Kelly SKY-SS has a shallow cup. Deeper cups favor a darker, richer sound; shallower cups provide more brightness and easier upper register.

Bach 1¼G vs Kelly SKY-SS

Name: Kelly SKY-SS
Brand: Kelly

The Bach 1¼G has a wider cup diameter, the Bach 1¼G 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 1¼G

• Trombone

Material—

Best suited for

🎻Orchestral playing — large cup for full, dark tone

📣High-volume projection — open throat for power

Mouthpiece B

Kelly SKY-SS

• Trombone

Lead

Material316 Surgical Stainless Steel

Best suited for

📋Professional lead trombone

Material

The Bach 1¼G is described as unspecified, and the Kelly SKY-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 1¼G details Kelly SKY-SS details Bach 1¼G equivalents Kelly SKY-SS equivalents

Bach 1¼G vs Kelly SKY-SS

Material

Playing Characteristics

What Do These Model Names Mean?

What Changes If You Switch?

Which is better?

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