Free Online Trombone Tuner

The trombone is written at concert pitch in bass clef (and tenor clef in higher passages), so written note equals sounding note and this tuner applies no transposition. The exception is the British brass band tradition, where tenor trombone parts are written in transposed B♭ treble clef, a major ninth above the sounding pitch. If you read those parts, switch the dropdown to Trumpet (B♭) and the letter names will match your page, though the octave shown will be the sounding one.

Set overall pitch with the tuning slide on the bell section, and only once the instrument is warm. Brass rises in pitch as it warms, often by ten cents or more between a cold first note and a warm one twenty minutes later, so play for a couple of minutes first. Most players tune on B♭3 in first position (written B♭ on the second line of the bass clef) and then check F4 in first position and B♭2 as well. Tuning a single note only sets the length of the horn: everything else depends on where you put the slide.

Slide positions are not evenly spaced. Because each semitone is a fixed ratio rather than a fixed distance, the gap between positions grows as you move out: sixth and seventh positions need noticeably more arm than the spacing between first and second would suggest. The pitch history makes this visible immediately. Play a chromatic scale down from B♭3 and watch whether the outer notes creep sharp, which is the most common pattern when a player’s positions are spaced too evenly.

Each partial also has its own tendency, and good players adjust the slide for them without thinking. The fifth partial (D4 in first position, and the notes a semitone apart through the positions) tends to sit flat on most tenor trombones, so players play it slightly short. The sixth partial (F4 in first position) tends slightly sharp and wants a slightly long position. The seventh partial (A♭4 in first) is nearly a quarter tone flat and is avoided in favour of A♭4 in third position. Alternate positions, F4 in sixth or D4 in fourth for example, have their own centre too, so check each one you use. The trombone slide position chart lists every standard and alternate position with the partial it belongs to.

Dynamics and register both move pitch. Loud playing tends to pull pitch flat as the embouchure loosens under high airflow, very soft playing tends sharp, and the low register below F2 is only reachable as pedal tones that most microphones struggle to read cleanly. Give the tuner a clear, sustained note at a realistic dynamic and let it settle for a moment before you read it. Then watch the history line on a long note: if the pitch sags near the end of the breath, that is air support, not the slide, and it is the single most useful thing a snapshot needle cannot show you.