Backbore: 692sL
An extremely efficient backbore. It is the 692s backbore but at the length of a conventional mouthpiece. This increases the straight bore leading to a full, but focused sound.

Backbore: 692s
A very efficient backbore. It causes the mouthpiece to be physically shorter than our conventional mouthpiece. When combined with shallow cups, it makes the upper register very efficient. When combined with very deep cups (like a "B" cup) it allows the darkness in sound of the cup while continuing to assist in the upper register.

Backbore: 2
Our standard backbore. More centered than a Bach #10 with excellent tone color and intonation. This backbore works well on all of our cups. It was the 2nd backbore Bob ever made.

Backbore: 69
Good for big band playing. Records well; bright, focused sound. This is very popular on our shallower cups (S and shallower). Good if you like to "power" the upper register. It was named because Bob developed it in 1969.

Backbore: 692
Darker and broader tone than our 69 backbore. Works great for those players who "power" the upper register. It is a combination of both our #69 and #2 backbore and thus the name, 692.

Backbore: 3
Flexible, big sound for the strong player.

Backbore: s
Our Symphonic backbore which is similar to some Bach and Schmidt backbores. Used in combination with deeper cups for a large, teutonic sound.

Backbore: X
Our physically largest backbore. Mostly used with rotary trumpets or by orchestral players that move large quantities of air.

Click on the backbore size below to see available rim and cup options.