The trombone is a medium-size cylindrical brass aerophone with a fairly low range. It is a mainstay of the brass section of orchestras, marching bands, and jazz bands. The feature that sets the trombone apart from other common Western instruments is its slide.

Figure 1: This bass trombone has valves and extra tubing to help it get the lowest notes, as well as the moveable slide (out in front of the bell) common to all trombones.

A Bass Trombone

Like other orchestral brass, the trombone has a mouthpiece, a main body of tubing, and a bell. The basically cylindrical shape of the trombone's tubing (as opposed to the more conical baritones and tubas) gives the trombone a clear, direct, brassy sound that is very popular in jazz and band music.

The instrument changes pitch using a moveable section of tubing called the slide. As the slide moves out, the instrument gets longer, and the sound gets lower. You might be tempted to think this means that there is one note available for any possible position of the trombone's slide, but this is not the case. Most possible placements of a trombone slide give pitches that sound wrong or out of tune, because they fall in between the notes of the chromatic scale. These in-between notes are only used when the trombone plays a glissando, sliding between the notes on purpose. There are seven slide positions that do give scale notes. Having the slide all the way in is position 1; having the slide all the way out is position 7. The other positions are spread out in between, with several inches between one position and the next.

But of course, the trombone can get more than seven notes. Like the brass instruments that only have a few valves (trumpet and horn, for example), the trombone can use changes in the player's embouchure to get many different notes from a different harmonic series at each position.

Figure 2: The trombone can get many different notes for each slide position. Each position gives the player a different harmonic series of possible notes to play.

Seven positions, each a half step apart, will cover a tritone (about half an octave). This is plenty everywhere in the trombone's range, except at the very bottom, in between the fundamental and the second harmonic, which are a whole octave apart. So some trombones - especially bass trombones - have an extra length of tubing opened by a valve (called the plug or trigger) that allows them to play the rest of that lowest octave. (If you want or need to understand this paragraph, and don't, please see Harmonic Series.)

At one time, there was a complete family of trombones: a treble, which played in the same range as the modern trumpet, an alto, tenor, bass and contrabass. The instrument that is now commonly called "the trombone" is the tenor trombone. The trombone section of most orchestras and bands will also have a bass trombone, which has a deeper sound, a slightly lower range, and a fuller, more focussed sound on low notes. The only other trombone that is still played (although rarely) is the alto, which is smaller and higher than the tenor, but not as high as the treble.

Figure 3: Above and below are the practical ranges for the tenor and bass trombone. Experienced players may be able to play above and below these ranges, and exceptional players can play much higher notes.

Tenor Trombone Range

Figure 4:

Bass Trombone Range

Unlike most other wind instruments, the basic design of the trombone has not changed much for centuries. It was developed in Europe, first appearing as the sackbut in the 1400's. In the 1800's, when valves were being added to other brass instruments such as the trumpet and horn, there were also experimental valve trombones, but they never gained much popularity. A modern trombone may have one or two valves that help extend its range, but the main work of changing pitches is still done using the slide.

At first, the sackbut/trombone was used mainly as a church instrument. Its timbre was considered to blend well with voices, and its ability to use its slide to make the subtle changes in tuning needed for the different church modes made it ideal to accompany plainsong chant.

Possibly because of its strong association with church music, the trombone was used sparingly in orchestras until the late Romantic period. Even when it did appear in the concert hall, it was often used to evoke religion, mortality, or the supernatural. (Examples of this include Beethoven's Symphony No. 5, Rimsky-Korsakov's Russian Easter Overture, the appearance of the ghost in Mozart's Don Giovanni, and Weber's Der Freischutz, another opera with supernatural themes.)

The various trombones originally played in the clefs deemed appropriate for their parts, alto trombones playing mostly in alto clef, for example. Nowadays, beginning trombone players learn bass clef, and most modern parts for both tenor and bass trombone are in bass clef. However, it is not uncommon for older parts to still appear in their original clef; the first trombone part may be in alto clef, for example, the second in tenor, and the third in bass clef. Or more than one clef might appear on the same part.

Eventually the organ replaced the trombone in church music, the association faded, and the trombone became a full member of the orchestra. It also became a popular member of many kinds of bands, and its strongest association these days is probably with marching bands and jazz bands.

Trombones are a perennial favorite band instrument. Listen for trombones in jazz bands, particularly "big band" music (Tommy Dorsey was a trombone player) and dixieland jazz. Popular marches like Sousa's The Stars and Stripes Forever and National Emblem, and King's Barnum and Bailey's Favorite (to name just a few examples out of many) also tend to feature the trombone, sometimes on melody, but even more often in the countermelody. Most smaller brass ensembles will have at least one trombone: brass quintets and the works of Gabrieli (originally written to be played in church by sackbuts and other early brass instruments) are the easiest to find. Trombones usually play a supporting role in orchestras, but you may want to look up the pieces mentioned in the history section above. Other orchestral pieces that feature low brass, including trombones:

The trombone may be considered to be "in B flat", since its first position gives a B flat harmonic series, but it is usually a non-transposing instrument with concert-pitch (C) parts. Modern trombone music is normally written in bass clef. However, as mentioned above, older trombone parts were often written in alto or tenor clef (and very occasionally treble). So parts to many famous classical pieces are still in these clefs, and modern trombone parts also occasionally use tenor or alto clef. These parts are also non-transposing, concert-pitch parts. Most American band and jazz music has the trombone reading mostly bass clef, and usually at concert pitch. But British brass bands often have the higher trombone parts written in treble clef as a transposing B flat instrument. Thus many trombone players will be comfortable reading parts in whatever clef you would like and even transposing on sight; but if you are writing for a particular player or situation - brass band, for example - you may want to find out what the preferred part is.

Trombones have a bright, brassy timbre that is easily heard even outdoors or even in a large ensemble. Because of long-standing association with certain types of music, the sound of a trombone is ideal for marches, fanfares, and solemn processionals, but also any time you want a jazzy sound.

Remember that glissandos are a trombone specialty, and that several different kinds of mutes are available for different timbres - some very popular for jazz.

Because of the realities of changing notes with a slide, the trombone is not as agile as many other instruments. Do not write long passages of very fast notes. Even short passages of very fast notes are not advisable in some keys. Be aware that slurring smoothly is more difficult for trombone than for valved brass.