The Structure of the Tuba
A Conical Tube as Long as 9.6 Meters

On a tuba, the tube is always conical and its bore gradually increases from the blowpipe to the bell. Only the slides, however, are untapered. Slides refer to tubes through which air flows only when the valves are depressed.

The diagram shows a rotary-valved tuba with a row of four round devices near the center of the instrument. These are the rotary valves. If you depress the levers on the left, the first lever opens the first slide tube, the second lever opens the second slide tube, the third lever opens the third slide tube, and the fourth lever opens the fourth slide tube. The pitch drops in proportion to the increased tube length in each case. This is the same mechanism that a trumpet uses: the first valve lowers the pitch one tone, the second valve a semitone, the third valve one and a half tones, and the fourth valve two and a half tones.

Names of the parts of a tuba

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Full view

Select any name to zoom in on the part Bell First tube Second tube Third tube Fourth tube Fifth tube Slides Rotary valves Mouthpiece Main tuning slide Water key Levers

Select any name to zoom in on the part.

 Download all of the tuba names 

The next diagram shows how the air travels when you blow through the mouthpiece. For the tuba with the lowest tonal range (the B♭ tuba), your breath goes approximately 5.40 meters when no valves are depressed. That increases to approximately 9.60 meters, though, when all the valves are depressed.

Example of how air flows through the tuba