Why learn to transpose?
Transposition is a fundamental skill of all professional trumpet and horn players, particularly those who play in orchestras.
Historically, brass instruments (other than the trombone and its predecessors) had no valves, which limited them to the notes of the “open” horn. Baroque composers wrote for the extreme high register of the instrument — above the 8th partial, where notes are closer together, allowing a full major scale (with some fudging of the pitch of the 4th scale degree). But few players could play in this strenuous ranges, and it still did not enable a full set of chromatic notes.
So classical composers settled for giving trumpets the “bugle notes” — the root, fifth, and third scale degrees (1, 3, 5, or C, E, and G). Trumpet players made use of tuning crooks of different lengths to play music in different keys.
Even after keyed bugles, and then valved cornets and trumpets, were invented, composers continued to write for trumpets in different keys, including A, Bb, C, D, Eb, E, F, and G.
This compositional habit lasted well into the 19th century, even as the music became highly chromatic. Many of the symphonies of Mahler, for example, are written for Trumpet in F. If you want to play these symphonies (and others like it) on a Bb or C trumpet, you need to learn how to transpose.
There are other reasons a musician may choose an instrument other than the one for which it was written:
- It may put the part in a more comfortable range for the instrument
- It may solve difficult fingering problems
- It may deliver the response and/or tone quality the player prefers for the piece. For example, higher trumpets have a crisper response and a lighter sound.
Transposition also gives you the ability to play music written for other instruments — such as violin, or horn, or sax — that are in C, F, or Eb respectively. You can play duets with your friends!
Finally, transposing is a fun mental challenge! So how do you do it?
How to Transpose
When I started transposing, I simply learned to think “every note up a whole step (e.g. from Bb to C) or, “every note up a fourth” (e.g. from C to F). But that is a bit of a brute force method. The following is how I was taught to do it by Don Green, who was at the time the Principal Trumpet player in the Detroit Symphony Orchestra.
Ask yourself:
- What is the key of the horn I have in my hand? (C trumpet, for example)
- What is the key of the horn for which the piece was written? (Eb, for example)
- Is it higher or lower? (higher)
- By what interval? (a minor third)
- What is the difference between those keys? How many sharps or flats are added or subtracted going from my key to the new key? (C is no flats, Eb is three, so add three flats)
- What is the WRITTEN KEY SIGNATURE of the piece? (G, for example; one sharp)
- Add or subtract the appropriate number of flats or sharps to the written key. This is your new key! (add three flats to one sharp, and you get two flats — the key of Eb!)
- SOLUTION: Play up a third into the key of Eb
Another example:
The Tchaikovsky Piano Concerto No. 1 is written for Trumpet in F. I chose to play it on the C trumpet. C to F is up a 4th, adding one flat. Since the written key of the piece was C, that meant I was playing up a fourth into the key of F, which has one flat (Bb).
If I was to play the Tchaikovsky on Bb trumpet, I would be going from Bb to F, which is up a fifth (a more difficult interval), removing one flat from the written key of C (which is the same as adding one sharp), putting the piece in the key of G (one sharp).
Where it gets tricky is when you see accidentals. You have to recognize whether the accidental is a “courtesy” accidental (i.e. reminding you to play a flat or sharp that is already in the key signature), or whether it is truly changing the note. But otherwise, it works exactly the same way — a flat lowers your transposed pitch ½ step; a sharp raises it ½ step. In the Piano Concerto, Tchaikovsky at one point wrote a B#. Because I would otherwise play an E on that note, I knew to raise that E to an “E#”, (basically an F).
Of course, a professional player quickly learns their part well enough that the page is simply reminding them what to play. The hard parts are worked out in practice, so that when it comes to rehearsal, they know it well enough to focus on ensemble, intonation, etc. But it all starts with transposition!