'Transposing instrument' is simply a short-hand term for an instrument whose standard written music is shown at a different pitch from that at which it sounds.
That's all! But in view of the very real confusion they can sometimes cause, we'd better say some more. The details below include tables of transpositions of some of the more common instruments, and to emphasise the simple utility of the 'transposing instrument' convention, the woodwind will be presented first. But before that, some general considerations.
What's in a name?
Names of transposing instruments define the note which sounds when the player reads a C on the music.
For example when the player of a B clarinet (a typical 'transposing instrument') reads a C, he sounds a B, and it will sound in tune with a violinist who is both reading and playing a B (as the violin is not a transposing instrument). When the player of an A-clarinet reads a C, he will sound an A. and so on.
The instrument names can also hint at the octave: a B clarinet sounds a tone lower than its written music; a B bass clarinet sounds an octave and a tone lower than its music is written; a B contrabass clarinet sounds two octaves and a tone lower than its music is written.
But sometimes the composer or arranger just has to know: a piccolo sounds an octave higher than its music is written; and a guitar sounds an octave lower than the music is written, with no real clues in the name.
Important: Remember that 'transposing instrument' is (confusingly) not a description of the instrument but rather of its written music convention. There is nothing 'B-flatty' about a B clarinet, and nothing 'effy' about a cor anglais; it's just the way their music is set down for the convenience of the players!
This is particularly important when considering instruments with more than one standard convention for the written music (there are only a few). Sometimes an instrument has to be regarded as a 'transposing instrument' when reading music written with one convention and as a 'non-transposing instrument' when reading music written with another. Trombones and tenor voice are cases in point (see below). Schizophrenia can be avoided, as long as one remembers 'transposing instrument' describes the music, and not the instrument itself.
Octave transposing instruments
Instruments which sound exactly an octave different from their written music, are included in the category 'transposing instruments'. They are just a special case, and there are quite a lot of them. They include: piccolo, double bass, guitar, bass flute, contrabassoon, C-melody sax, heckelphone, tenor voice, and descant and bass recorders (but see below for a discussion of recorders).
Almost all transposing instruments other than those where the transposition is an octave read solely from the treble clef. The most prominent exception is the French Horn in F which can read from both treble and bass clef. A number of the octave transposing instruments read from bass clef, and, unusually, the double bass even sometimes moves into tenor clef (still sounding an octave lower than written).
In what follows the transpositions of instruments are given, categorised by family. The accompanying tables show the instrument names, the clef(s) from which they read, and their transposition.
Nomenclature: in much of what follows the syntax used to describe transposing instruments is of the form 'B Clarinet'. The alternative form 'Clarinet in B' is just as common and is also used in this article.
Modern woodwind families
Modern woodwind families provide the widest range of examples of transposing instruments. The tables below provide a list of some of the commoner members of the families in use today, as well as some of the slightly less common ones.
|F Basset Horn||P5|
|E Alto Clarinet||M6|
|B Bass Clarinet||M9|
|E Contralto Clarinet||M13|
|B Contrabass Clarinet||M16|
The clarinet was invented by Johann Denner in about 1700. It rapidly became clear that the kinds of cross fingerings used to get (eg) B or G on a recorder, produced an unacceptably muffled tone on a clarinet. Clarinets were therefore built in a variety of sizes, so that one could be used whose natural scale fitted with the key of the piece being played, removing the need for too many cross-fingerings.
By about the 1830s, the technology was available for reliable construction of the systems of keys, springs, and pads we see on modern clarinets. (The 'Boehm system' - named after the man who had recently developed the key-work on the flute.) These largely eliminated cross-fingerings, and most 'normal-sized' clarinets fell out of use, leaving the B and A clarinets used in symphony orchestras today. However the same technology meant that keys could operate pads on distant holes, and so instruments were no longer constrained by the size of the human hand. The family grew with the addition of larger members which are now standardised as E-alto, B-bass, E-contralto (or contra-alto), B-contrabass.
It is worth emphasising again that the same written note is fingered in exactly the same way on all the clarinets tabulated!
[An exception is that some older bass clarinet parts are written in the bass clef sounding a tone lower than written, the so-called 'German notation'. Blatter (see bibliography below) makes it clear that this notation is obsolete, and not recommended.]
|G Alto Flute||P4|
The flute was the first of the woodwinds to gain a comprehensive system of keys and pads - developed by Boehm, starting in 1831. The same technology, as with the clarinets, allowed larger flutes to be built.
|E Sopranino Sax||m3|
|B Soprano Sax||M2|
|E Alto Sax||M6|
|C Melody Sax||P8|
|B Tenor Sax||M9|
|E Baritone Sax||M13|
|B Bass Sax||M16|
|E Contrabass Sax||M20|
The saxophone was invented by Adolph Sax in about 1841, the time when the established woodwind families were being developed with more key work, and augmented by the larger family members which this allowed. Sax was reputedly looking for a woodwind bass instrument with a bit more 'oomph' than the bassoon, to balance the brass in military bands, and started by putting a bass clarinet mouthpiece on an ophecleide. The saxophone family is unusual in that smaller members came along later. The modern family is fairly regular with members in B and E. (The C-melody sax is now rare, but is prominent in 1920s and 30s jazz recordings by its premier exponent Frankie Trumbauer.)
|Oboe d'Amore in A||m3|
|Cor Anglais* in F||P5|
The most usually encountered members of this family are the oboe in C and the cor anglais in F.
The bassoons are in C with the contrabassoon transposing down an octave. It does this even if its part wanders into tenor clef, making it one of very few transposing instruments to use a tenor clef.
|Great Bass Recorder||P8|
The conventions for writing music for recorders long predates the transposing instrument convention used by modern woodwind families. They do fit into the general scheme of transposing instruments, but not quite so neatly as the woodwind families above. Therefore, if there is any scope for confusion, this is the section in which to find it - you may want to skip it on first reading! Otherwise here goes.
All recorders are in C. Some are at concert pitch (ie are non-transposing instruments); some transpose at the octave, and one transposes two octaves.
Some recorders read from treble clef; others read from bass clef. As far as their properties as transposing instruments go, the table says it all.
A note on nomenclature:
'descant recorder' = 'soprano recorder'
'treble recorder' = 'alto recorder'
But now it gets complicated. Recorders do not follow the pattern of other transposing instruments. On a clarinet you can read any note and play that note with essentially the same fingering on any member of the family. The same is true, within the families, of flutes, saxophones,... But this happy situation does not prevail with recorders. Their fingering system was developed before the modern concept of transposing instruments. There are two variables: the clef and the natural scale of the instrument.
If you cover all the holes and lift each finger in turn (with minor elaborations to control tuning) you obtain the natural scale of the instrument. With modern woodwind families the natural scale is written the same for all members of a family, though it sounds different. With recorders there are two possibilities: a scale of C (both written and sounding) or a scale of F (also both written and sounding). There are therefore four cases overall:
Confusion alert: recorder players will often refer to those instruments with a natural scale of F as being "in F", and those with a natural scale of C as being "in C". This has nothing to do with their properties as transposing instruments, in which context they are all in C (because when you read a C, you sound a C).
- natural scale of C; treble clef; (garklein, descant, tenor)
- natural scale of C; bass clef; (great bass)
- natural scale of F; treble clef; (sopranino, treble)
- natural scale of F; bass clef; (bass, contrabass)
corresponding with four different fingering schemes. Recorder players are accustomed to this, and don't think of it as in any way complicated. From the perspective of modern woodwind, where the simple elegant 'transposing instrument' mechanism is fully developed, it looks a complete mess. It means that (for example) someone who has learned descant recorder can automatically finger tenor and (if they have small fingers) a garklein, but playing the others requires further training and practice. Similarly, if you have learned treble, then sopranino has the same fingering, but the others are different. In summary, while many recorders do transpose (at the octave), recorders do not take full advantage of the "transposing instrument mechanism".
|B Piccolo Trumpet||m7|
|A Piccolo Trumpet||M6|
|E Bass Trumpet||M6|
|B Bass Trumpet||M9|
The most usual trumpet is the one in B, though nowadays C-trumpets are becoming common in orchestras. Nevertheless they have been built in quite a range of sizes. Of those listed here, the piccolo trumpet in A is likely to be a piccolo trumpet in B with a removable crook, and the bass trumpets are encountered only rarely.
Brass bands and orchestras
Brass bands employ cornets, saxhorns of various sizes, trombones, and tubas. The most standard symphony orchestra will employ trumpets (covered above), trombones, and tubas. The convention for written music for trombones and tubas in these two ensembles is completely different: in brass bands the trombone and tubas are transposing instruments; in orchestras they are not.
|Brass band convention||Orchestral convention|
|E Soprano Cornet||m3|
|E Tenor Horn||M6|
|B Baritone Horn||M9|
|Bass Trombone||-||Bass Trombone||-|
A number of observations are in order. The military band (or concert band) convention for these instruments is the same as the orchestral, though, for example, Euphonium parts in the 'B treble' convention are sometimes provided as alternatives. (And sometimes similarly trombone and tuba parts.)
The transposing instrument convention in brass bands has a slightly different context from that of the woodwind, in that players do not quite so routinely double on different brass instruments. The British Brass Bands grew up in the 19th century, to a large extent in mining communities, in the context of a more general liberal movement to give the working man access to culture and education. Of course the average pit worker could not afford to buy an instrument and these tended to be owned by the band. A new recruit could try a few before finding the one he was most suited to, and established players could make a permanent move from one to another, for whatever reason. It was therefore extremely helpful that the fingering of the (usually) three valves on all instruments was the same for the same printed note.
Tuba parts in the orchestral convention are written at concert pitch. The size of tuba to be employed is up to the player, who will be accustomed to different fingerings on different sizes of tuba, very much analogous to the case of recorders discussed above.
The 'sousaphone' is a tuba in B with its plumbing arranged in a shape which will go around the body of the player, to facilitate playing while marching.
|French Horn in F||P5|
The French Horn
The French horn is pitched in F, sounding a fifth lower than written. Unusually its parts can use treble and bass clefs.
(Some older French Horn parts are written in a convention, now obsolete, where the parts sound a fourth higher than written when they're in the bass clef, but still lower than written when in the treble clef.)
The orchestral strings
For the most part the orchestral strings provide a complete contrast to the families of transposing instruments. Dating (in terms of a complete family) from a much earlier era, their written music convention uses clefs rather than transpositions to avoid leger lines. Violin uses treble clef, the viola the alto clef, and the cello the bass and tenor clefs. In each case the music is written at sounding pitch. The violin, viola, and cello form a family in exactly the same way as the woodwind families, simply being essentially the same instrument in different sizes. Each has four strings tuned in fifths, but with the lowest string being G below middle C, C one octave below middle C, and C two octaves below middle C. Seen from the (perhaps heretical) viewpoint of the saxophonist (say) viola, and cello would be ideal candidates for being 'violins in F' and being notated on treble clef like a violin but sounding a fifth and a twelfth lower. But that is not the way that history went, and their peculiar (by comparison with woodwind families especially) use of clefs has chronological priority. It should also be observed that string players do not tend to double on different members of the family, and it may be that the different sizes of the instruments would be a large enough barrier to this, even if their reading conventions were the same.
The double bass is different. A less modified member of an older family of viols, its strings are tuned in fourths. Its music is written one octave higher than it sounds, and so it is a transposing instrument. Like the contrabassoon discussed above, it remains an octave transposing instrument even if its music wanders into the tenor clef.
|5-string G Banjo||P8|
Of the plucked strings, the guitar and banjo sound one octave lower than written music, but use of a capo can essentially introduce a different transposition.
Vocal music is shown at concert (ie sounding) pitch, with one exception. In a 'short score' for vocal quartet, where soprano and alto parts are shown together on one staff, and tenor and baritone/bass are shown together on another, the tenor+baritone staff has a bass clef, and the tenor parts are written at sounding pitch, like all the others. However in an expanded score where each voice has its own staff the tenor part is usually written with a treble clef, and it sounds an octave lower than written. In this latter convention the tenor voice is a 'transposing instrument'. Sometimes a little 8 is drawn beneath the treble clef, as a reminder that this part is different - because of the transposition. Both conventions are included in the table on the right.
It can be seen from the instruments given above (and the list is far from exhaustive) that 'transposing instruments' are not in any way exceptional, but in many ways constitute the norm - especially for 'modern' instrument families.
How is the transposition marked on printed music?
On an instrumental part, the transposition is most usually marked at the top of the part in plain text - for example 'Alto Sax in E'. If that part is to be played on another instrument for any reason, it is this label which tells you that it should be played to sound (in this case) a major 6th lower than written.
On a full score, the instrument's stave will be labelled in the same way.
The so-called 'octave clefs' (clefs with a little 8 above or below) provide an additional or alternative way of designating parts which transpose by an octave, up or down respectively. There is no way of designating other transpositions (apart, possibly, from 15ma) with this kind of notation, and it is not generally used today, except in two particular contexts: the tenor voice in vocal music (see above) and in early music consorts. In both cases the only transpositions of interest are octave transpositions.
In music for recorder consort the little 8's are included by the clefs in some editions and not in others - they are completely optional. They can be useful in cases where you wish to write the music down for an uncertain early music consort, where you don't want to label a certain part 'descant recorder', but do want to indicate that it is designed to sound an octave higher than written. That way when any given consort plays the music, it can do so with the parts in the correct relative octaves.
Parts which change transposition part way through
Parts can change transposition part way through. In some contexts it is commonplace. For example:
- Orchestral clarinet players use both B- and A-clarinets as a matter of course. Parts may switch from one to the other.
- Alto and baritone saxophone parts in a big band often involve doubling on clarinet or soprano sax introducing transposition changes from E to B instruments.
In such cases the music is marked (eg) 'to clarinet in B' and (with luck) there'll be a long enough rest for the player to put one instrument down and pick up another.
Another (now obsolete) example is provided by old French Horn parts where the transposition is a fifth down when the treble clef is in force and a fourth up when the bass clef is in force.
Writing music with Mozart
Mozart comes with a database of transposing instruments containing all those above and more. When starting a new score for a new ensemble, you just select the instrumentation from the lists of available instruments. Mozart will take care of the transpositions, and allow you to view your score at 'written pitch' (the usual convention for scores, where each instrument's music is shown the way the player sees it on his part) or at 'concert pitch' where all parts are shown at the pitch at which they sound (give or take octaves introduced to keep the number of leger lines under control).
Useful references on the theory of transposing instruments, orchestrating for them, and writing their music out include:
- Elaine Gould, "Behind bars -the definitive guide to music notation", Faber 2011
- Gardner Read, "Music notation - a manual of modern practice", 2nd ed., Taplinger 1979
- Eric Taylor, "The AB Guide to music theory", vols 1 and 2, Associated Board of the Royal Schools of Music, 1991
- Alfred Blatter, "Instrumentation and Orchestration", 2nd ed., Schirmer 1997