Online Trombone

A slide, nine feet of tube, and the harmonic series

A tenor trombone is one brass tube about nine feet long, and at any length a tube plays a whole ladder of notes — the harmonic series. Your lips choose the rung by how fast they buzz, and that rung is called a partial. The slide is a U of tubing that makes the tube longer, and a longer tube moves the whole ladder down. So every note is two things at once — a partial and a slide position — and playing the trombone is knowing which pair gives the note you want.

What makes it a trombone and not a trumpet is that the slide is continuous. A valve is a switch; the slide can stop anywhere. The seven positions are just the places a half step apart, the player puts every note in tune by ear, and moving the slide while you blow bends the note smoothly from one pitch to the next — the glissando.

Play it two ways. In Notes, tap the note you want: the drawing moves its slide to that note’s position, names the partial, and lists the alternates. Every key carries its position number, so the keyboard is the chart. In Slide + air, play it like the real thing: the air ladder is on the left, the slide on the right, closed at the top and fully out at the bottom. Hold a rung and drag the slide, and the pitch glides with it.

Trombone slide position chart, C2 to F5

Every note on a tenor trombone, with its standard position, the partial it is played on, and the alternates. The rule behind the chart is short: play each note on the nearest partial at or above it, and let the slide take it down the rest of the way. That is why high notes have so many alternates: the partials crowd together, and there is always another one a few positions further out.

The first four rows only exist with an F attachment: a plain tenor has nothing between the pedal B♭1 and E2. T1 to T6 are the positions with the trigger held. The F-trigger column lists only T1 and T2 — the two that save a long reach to 6th or 7th — and the F side has other alternates further out.

Where the seven positions really are

Each position lengthens the tube by one more equal-tempered half step, and because each step is a proportion of a longer tube, the positions get further apart as the slide goes out. On a tenor, second position is about 8.2 cm (3.2 in) from first, and seventh is about 10.9 cm from sixth. That is why a student’s 6th and 7th are usually short: the arm expects even spacing.

The alto trombone in E♭ is a shorter tube a fourth higher, so the same seven half steps take less slide: its seventh position is about 42.6 cm out, against the tenor’s 56.8. Every position is proportionally closer in, which is what makes an alto feel cramped to a tenor player.

In tune: the 5th partial, and the D in first position

A partial is where the harmonic series puts it, not where the piano does. The 5th partial — D4, C♯4, C4, B3, B♭3, A3 and A♭3 down the positions — is about 14 cents flat, so every one of those notes wants the slide a little in, about 1.1 cm short of the mark. Except the first: D4 in first position cannot be brought in, because the slide is already closed. A player lips it up, or plays it in 4th position on the 6th partial.

The 7th partial is about 31 cents flat, too far to lip, which is why it is off the chart. It is still useful for alternates — a slide brought in by several centimetres fixes it — except in first position, where the note it is meant to give, A♭4, would need the slide 2.4 cm shorter than closed. So A♭4 is played in 3rd. On the same partial G4 sits in a short 2nd position, about 2.6 cm in from the mark — the alternate players call a raised 2nd. The 11th partial is about 49 cents off, almost exactly a quarter tone, and nobody uses it.

On the instrument, switch to Slide + air and turn on Free slide. The magnet comes off the positions, the pitch is wherever the slide is, and the readout says how many cents you are from the note and which way to move. Blow the 5th rung in 2nd position and you will find the in-tune spot just above the mark.

The F attachment

Pick Tenor + F trigger above the instrument. The trigger switches about 91.8 cm of extra tube in — a perfect fourth — and the whole horn drops from B♭ to F. On that longer tube each half step takes more slide, so the same 62.5 cm of slide travel holds only 6 positions, T1 to T6, and T6 is already a little past seventh. That puts the lowest trigger note at C2, and the B below it out of reach unless the attachment’s own tuning slide is pulled.

In Slide + air, hold the F trigger button (or Shift) and the slide grows a second set of marks, T1 to T6. The ladder re-labels itself with the notes the F horn gives.

How to play it

Hold a note to blow it and let go to stop — a trombone sounds only while air goes through it. In Notes, slide along the keys without lifting to play legato. On a phone the keyboard is wider than the screen: drag the strip above it to move along the instrument, and it follows a song or a practice note on its own.

In Slide + air, hold a rung of the ladder with one thumb and drag the slide with the other. With one finger or a mouse, tap a rung to choose it, then press the slide: pressing the slide blows the chosen rung. Move up or down the ladder while you blow and the lips jump a partial — a lip slur. The slide snaps to the positions until you turn on Free slide.

On a computer keyboard, in Notes, the letters climb a semitone at a time from Q, the low F in 6th position. In Slide + air, 1 to 7 move the slide to a position, ↑ and ↓ push it by hand, the row from Q blows the partials — Q the pedal, W the 2nd, R the 4th — and Space blows the one chosen. Hold R and press 1 then 5 and you have just played a glissando from B♭ down to F♯.

Songs to play

Press Play a song under the instrument and pick one. The songs are read an octave down, in the trombone’s own register, and in B♭ — the band key — they sit between the low F and the F at the top of the bass staff. A tenor plays all 22 of them in every key on the menu but G major, where it plays 21. The alto, a fourth higher, plays 21 in B♭ major, 22 in F major, 22 in E♭ major, 21 in C major and 6 in G major. Play shows each position as it sounds, Practice waits on the next note and moves the drawn slide there first, and Play along closes a ring on each note in time with the music — on the keys in Notes, and on the slide itself in Slide + air.

Tenor, F trigger or alto — and why no bass

The chips above the instrument are three tubes with one physics between them. Tenor is the plain B♭ trombone in every school band. Tenor + F trigger is the same horn with an F attachment, the usual step up. Alto in E♭ is a fourth higher with a shorter slide, the instrument of Mozart’s and Haydn’s trombone parts. There is no bass trombone here, on purpose: it adds a second valve, to G♭ or to D, built independent or dependent depending on the maker, and a chart for one would be wrong for the next. A trombone part in bass clef is written at concert pitch, so the notes here are the notes a piano plays.

More instruments you can play here

The online trumpet is the same instrument with valves where the slide is, and the online tuba is the brass family’s bottom, four valves and a pedal. Got a real trombone that sounds off? The trombone tuner listens through your microphone and walks you through checking every position.

Frequently asked questions