Pitch of brass instruments

As bore width increases relative to length, it becomes easier for the player to resist the instrument's tendency to jump to the second harmonic instead of producing the fundamental frequency.

These terms stem from a comparison to organ pipes, which produce the same pitch as the pedal tone (fundamental) of a brass instrument of equal length.

[3] Certain low brass instruments such as trombone, tuba, euphonium, and alto horn are whole-tube and can play the fundamental tone of each harmonic series with relative ease.

Furthermore, the low brass often use extra valves to extend their range uniformly, since the fundamental is chromatically discontinuous with the lowest 2nd harmonic reachable on a three-valve instrument or via the seven-position slide on a trombone.

The less common double slide contrabass in low B♭ is often fitted with a valve in F. All these instruments are notated in bass clef at concert pitch.