A while ago a miffed alto sax player asked me why on Earth, at the modulation, I’d written his part in seven flats. ‘We’re supposed to know all the keys, aren’t we’ I replied as diplomatically as I could. There were no jazz solos at this point, the music moved in simple durations at a steady tempo and I’d been very generous with cautionary accidentals. The nominal key of the piece put everyone in a flat key and it seemed a good idea to stay with flat keys at the modulation. Thinking about it, I decided he had a point, so I changed the score to 5 sharps at the modulation, the enharmonic equivalent, with appropriate changes to other instruments. The trombones would still be far happier in seven flats but they’ll be in the bar by now anyway.
To arrive at seven flats Cb major from a literal transposition, the original ‘concert’ key would have to be Ebb major. The minor equivalents would be Cb minor to Ab minor. The particular modulation I’d used was to a mode, not to another major or minor key, so that double flats didn’t occur anyway.
I remember playing exercises in double flat and double sharp major and minor keys because anything seemed easy afterwards, rather like climbing a hill after removing a heavy kit bag. I’m not convinced there’s any other use for them, although correct chromatic ‘spelling’ in any key is important, to avoid confusion (see ‘Chromatic Harmony’ in the book).
Most jazz and popular music is written around one side of the cycle of keys, not straying too far in either direction from the starting point C major/A minor = zero sharps or flats. String arrangements will stray further in the sharps direction and brass arrangements in the flats direction (if the sounds are synthesized, or sampled and enhanced, it makes no difference).
We’re used to seeing jazz arrangements in C, G, F, Bb, Eb, Ab and Db. Transposed up for the alto sax we get A, E, D, G, C, F and Bb. Notice how the world looks quite different through the eyes of the alto sax player. Bb brass band players complain about too many sharps, but if C major/A minor and G major/E minor are common keys, Eb instrumentalists (alto sax, ‘tenor’ horn – it’s an alto instrument – and Eb tuba) will be equally at home playing in three and four sharps.
Concert pitch bass trombone parts in brass bands are often in five, six and sometimes seven flats because it puts all the other (transposing) instruments in an easy key. Cb = Db and Ab for Bb and Eb instruments respectively. (Tenor trombones are treated as Bb transposing instruments in these bands for reasons I’ve never understood.)
Familiar habits will often be irrelevant when using less orthodox seven note scales, some of which use both sharps and flats in the key signature. In addition to extending tonality, the book encourages more adventurous modulations in terms of root movement than those favoured by a tradition that is still heavily influenced by classical thinking.
On the subject of keys we can’t let the matter pass without a reference to ‘key colour’. Since around 1550 AD all keys are made up of identical semitone building blocks (equal temperament). Imagine laying out thirteen of them on a table, from C to octave C. Now take the left hand block and move it to the right hand end. We now have the diatonic and chromatic material necessary for writing in the key of Db (or C sharp), but the only thing that has changed is pitch. The key is a semitone higher. I’ve read various attempts to explain that key-colour exists but I’ve yet to see a convincing argument.
The only other aspect of so-called key colour to consider isn’t really anything to do with tonality at all. It has to do with instrumental characteristics:
The more open strings that occur on sustained notes, the more resonant a string section arrangement will sound. Listen to the unison violins drop down to the open G string in Scheherezade in the slow melody. (A reminder that this piece is essential ‘reading’ for the orchestrator. Virtually every trick in the book is in there somewhere.)
Piano strings change construction from top to bottom of the register.
Guitars and bass guitars produce a fuller sound when the hand is in the middle of the fretboard.
Clarinetists have to work hard to equalize the tone quality of the weaker ‘throat’ tones which occur, annoyingly, right in the middle register. They then have the ‘break’ (register change) to contend with.
Some people even refer to the colour of individual pitches. Conditioning is a powerful force and if we lived in a world where the sky was green and the grass was blue our subjective response to these colours would change accordingly. Cause and effect are dangerous areas for the unwary in any scientific field.
Colour and ‘atmosphere’ in music are created by the interaction of the various elements available to the composer. It’s often easier to draw comparisons with the graphic or pictorial arts. A single spot of colour will appear more saturated if surrounded by black (and there are lots of different ‘blacks’ as any printer will tell you). The humble common chord can have a powerful impact following a dissonant progression of chords. In other words there’s no practical purpose in assessing any individual component in isolation.
Key changing and pitch changing in general have been automated by music notation software but accidentals will often need to be edited to ensure they make sense. But then, we always check parts through don’t we, using our check list?
If you’re doing a vocal arrangement and you’re unsure about the key, which often happens in the real world despite all attempts to resolve the matter beforehand, it can be an idea to leave the score print out until after the first rehearsal just in case the key has to be changed. There’s a fair amount of work involved in printing score sheets on both sides (backing up), assembling them in the right order and binding with the stiffer card outer cover. If you’re on a once-only recording session it won’t matter what key the score is in for conducting purposes on the day.
It’s worthwhile bearing in mind that vocalists can ‘shout’ a high note with more confidence when they have the backing of the full band. Vocal arrangements will often use less usual keys because a semitone up or down can make a difference. So if you’re transcribing a vocal piece and you think it’s in E or B you might be right, especially if there’s a string section involved.
In the big band era Db was a favourite key partly because Db was the lowest note on the old baritone before they added the bottom C (bottom A to the player). This note (C) is two octaves above the lower limit for practicable use in music (= 16 cycles)*, below which the sound ceases to be heard as a continuous note. In the upwards direction you reach a point where only cats and dogs can hear the note. The ability to hear very high sounds diminishes quite early on in the ageing process giving rise to significant individual differences.
*P.S. I’m aware we talk of Hertz these days.