Which has a bigger cup — Bach 12E or Bob Reeves 4G/JF?

The Bob Reeves 4G/JF has a cup diameter of 26.00 mm / 1.0236 in compared to 24.50 mm / 0.9646 in on the Bach 12E — a difference of 1.50 mm / 0.0591 in. A wider cup generally produces a fuller, darker tone but requires more air support.

How does cup depth compare between Bach 12E and Bob Reeves 4G/JF?

The Bob Reeves 4G/JF has a deep cup while the Bach 12E has a shallow cup. Deeper cups favor a darker, richer sound; shallower cups provide more brightness and easier upper register.

Bach 12E vs Bob Reeves 4G/JF

Name: Bob Reeves 4G/JF
Brand: Bob Reeves

The Bob Reeves 4G/JF has a wider cup diameter, the Bob Reeves 4G/JF features a deeper cup.

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

The taper behind the throat leading to the shank. Affects projection and tone character.

Mouthpiece A

Bach 12E

• Trombone

Backbore—

Best suited for

📣High-volume projection — open throat for power

Mouthpiece B

Bob Reeves 4G/JF

• Trombone

Backbore—

Best suited for

🎻Orchestral playing — large cup for full, dark tone

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 12E details Bob Reeves 4G/JF details Bach 12E equivalents Bob Reeves 4G/JF equivalents

Bach 12E vs Bob Reeves 4G/JF

Playing Characteristics

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