Calculation of Trombone Slide Positions

Temperature (in F)

Key of Trombone

Desired Pitch


This Javascript calculates distances for slide positions for alto, tenor and bass trombones.

To use:

  • Enter the temperature in Fahrenheit in the first text box.

  • Select the key of the trombone from the available choices. For the bass trombone, the key represents the key that the instrument goes into after engaging the valve(s).

  • Select the desired pitch.

  • Select the appropriate octave. The octaves are given in terms of landmark pitches on the tenor trombone. For example, notes from Middle Bb to Low B are essentially those contained within the staff in bass clef.

Pitch Ranges

  • Press the Calculate! button.

The harmonic, slide distance and slide position are then given for the notes available on a slide of normal length.

The harmonics are given as a number, with "1" representing the pedal tone (a half-wavelength), "2" representing the octave above (a full wavelength), etc. Slide positions are calculated up through the 20th harmonic. Harmonics may also be referred to as 'partials' or 'overtones'.

The slide position is given relative to standard positions of a Bb instrument played on a Bb harmonic. For instance, with an F attachment engaged, a low E would be played at a position equivalent to 2.32, i.e., a flat 2nd position for a standard Bb horn.

I've been taught that the high F harmonic is especially sharp, so positions must be noticeably extended. However this calculation indicates that the deviation is small. On the other hand the D harmonic just below is quite flat, and ideally the slide would need to be brought in by over a centimeter to achieve a well-tempered pitch.

For an explanation of some of these calculations, see this page. Thanks to Benny Leonard for suggestions on improving this page.

November 21, 2014 • Jeffrey Clymer •  Email •  Home Page