How to Transpose Music at Sight

By E. H. Pierce

Anyone who has the patience to learn the major and minor scales thoroughly may at once study the indispensable subject of transposition.

The ability to transpose at sight is a very useful accomplishment for pianists who have occasion to accompany singers; also, the practice of transposing is a help to one’s general musicianship.

The first necessity to one who would master the art of transposition is a thorough and practical acquaintance with all the keys, both major and minor, as regards their signatures, scales and principal chords; this granted, it becomes merely a mechanical routine, requiring concentration and quickness of thought rather than any deep theoretical knowledge.

The transpositions most likely to be called for by singers are (in the order of frequency) a semitone down or up, a whole tone down or up, a minor or major third down or up. A transposition of a fourth, fifth or wider interval changes the tone quality of the piece so greatly as to alter entirely its character, and if made at all would require more properly an entire re-arrangement of the harmony rather than a mere literal transposition. This is particularly true of compositions in which part is to be sung.

For one’s first attempt there is nothing better than to take an easy song-accompaniment, a hymn-tune or a short piano-piece or study, in the key of C, and transpose it downward a semitone. This puts it in the key of C flat (seven flats) and all one needs to do is to imagine a flat before every note, including, of course, C and F, whose transpositions will be white keys, not black. If accidentals are met with, remember that a sharp with become a natural, a flat will become a double flat, and natural will become a flat.

The next step is to take a piece in any sharp key and transpose it to the corresponding flat key. The rule for this is only an extension of that just given; remember that the sharps in the signature will become naturals, and that all other notes will be flat. For instance, take the key of A: The F, C, and G, being sharp in the signature, will always be natural; the other notes, B, E, A, D, will be flat. Notice that the letters just last named are nothing more or less than the signature of the key of A flat, into which we are about to transpose. The same routine may be followed with any sharp key.

To lower a semitone when the key is already a flat key is slightly more difficult, though the difficulty will soon yield to honest effort. The rule will be: imagine the flats in the signature are double flats and everything else single flats. Should accidentals be met with, regard a flat as a double flat, a natural as a flat, a sharp as a natural.

It is recommended to practice the transpositions just described for a few weeks before going on to the next.

To Transpose Upward a Semitone

All the rules for this will be the exact converse of those given above. For the key of C, imagine seven sharps in the signature – that is, sharp every note. For accidentals, read a sharp as a double sharp, a flat as a natural, a natural as a sharp.

For keys having a flat signature, imagine each flat a natural and sharp all other notes.

For keys having a sharp in the signature, imagine each sharp a double sharp, and all other notes singly sharped.

To Transpose Upward or Downward a Whole Step

Here is the first question to ask ourselves: “What is the signature of the new key?” Suppose the original is in C, and we wish to transpose downward to B flat: the signature of B flat is “B flat and E flat.” Hold this firmly in mind and act accordingly, putting every note downward one letter and observing the signature of the new key. Thus:

  • C will become B flat
  • D will become C
  • E will become D
  • F will become E flat
  • G will become A
  • A will become G

The chief difficulty will be in the matter of accidentals, as it is impossible to frame any such simple and convenient rule of thumb as that given for the transposition of semitones. Generally speaking, a sharp will remain a sharp and a flat will remain a flat, but there are sure to be exceptions: for instance, in the transposition just described, an accidental C sharp would become, not B sharp, but B natural. The best thing we do when we meet an accidental is to ask ourselves what note is a whole step below this (or above, as the case may be). A thorough elementary knowledge of harmony is a great help in this and similar cases, yet I have known many musicians, especially orchestral players, who had succeeded in becoming very expert transposers without any such knowledge.

To Transpose Upward or Downward a Third

This is the transposition usually called for when an alto voice sings a soprano song, or the reverse. Fix firmly in mind the signature of the desired new key, and read each note which is on a line as if on the line above (or below, as the case may be), each note on a space as if on the space above (or below, as the case may be). The interval may be either a minor or a major third, according to the signature chosen: for instance, if the original is in B flat, transposing to the key of G would be lowering it a minor third; transposing it to the key of G flat would be lowering it a major third. Accidentals constitute the chief difficulty, but are dealt with by considering what interval is in question – a minor or major third – and acting accordingly. For the benefit of those who have not studied harmony, we would say that a “minor third” is obtained by counting four semitones; a “major third”, by counting five. Thus, from C to E flat we count “C, D flat, D, E flat” four semitones; from C to E we count “C, D flat, D, E flat, E” five semitones.

Composers writing in Sonata form, Rondo form, or Fugue always meet with the necessity of transposing certain of their themes a fifth or a fourth in the course of their work. Those writing or arranging for orchestra are also obliged to be specially well versed in transposition, as the parts for clarinet, cornet, trumpet, French horn, etc., are written in keys other than which they sound. The reason for this lies in the early history of these instruments and the technical incompleteness of their original forms. It is an interesting subject but would lead us too far afield to discuss at present. We shall give no special rules in regard to these transpositions for the reason that persons engaged in such activities as those just indicated have, as a matter of course, reached a point in their musical experience where help from an article of this kind is unnecessary.

The Perfection of the Art

When one has reached a high degree of musicianship and has been long accustomed to the task of all sorts of transpositions, he will at last reach a point where all such mechanical rules as we have endeavored to present for the aid of beginners may be thrown aside, and the task accomplished in quite a different way. One then reads the music and hears it inwardly, both in its melody and its harmonic scheme and simply plays it by instinct in the key desired, the mental process being quite similar to playing by ear a tune that one has heard but never seen in print. The writer, on just one occasion in his lifetime, found himself called upon to transpose at sight a short Anglican chant into a key distant an “augmented fourth” – probably the most difficult transposition that could be named. Instead of attempting to do so by following out any rule, he managed by extreme concentration of mind to memorize the chat in a few moments, after which he played it successfully in the desired key, rendering it “by ear,” so to speak. Problems of this extreme sort are fortunately very rare.

Technical Value of Transposition to Pianists

It is one weakness of nearly all the standard etudes for piano, aside from those intended for very advanced players, that they stick too closely to the key of C and its nearly related tonalitics, giving the student insufficient acquaintance with the black keys. Hanon’s Virtuoso Pianist, otherwise a work of surpassing excellence, suffers from this defect, while it is almost ludicrously in evidence in Czerny and other older writers. Pischna cannot be accused of it, nor Wolff in his Little Pischna, but the former is only for very advanced pupils, and both are painfully unmusical to the ear. The writer has found it very beneficial to require pupils, even as early as grade 3 or 4, to transpose their studies occasionally. The exercises in the first part of Hanon, which are all in the key of C sharp or C flat, without changing the fingering. True, this brings the thumb occasionally on a black key, but he has never found any good reason to uphold the superstition of the earlier school of piano teaching, which apparently takes for granted that the black keys are in some mysterious manner harmful to the thumb.