Transposition is a musical term for moving notes higher or lower to change key. As an arranger, the question I'm asked the most is: "Why is the music in this key?" Though more often than not, questions are phrased as expletives, "Pachelbel wrote his Canon in D minor for a reason, get a clue!"
So why do arrangers transpose? Why not keep everything in it's original key and for that matter why don't composers always write in C, as it has no flats or sharps?
Choosing the key of a piece is somewhat like choosing a seat in an airplane. Though all the seats are sort of the same, everyone has preferences, for various reasons.
Perhaps it's a day flight and you want to look at things, so you choose a window seat. You may want to be near the emergency exit because you have a fear of flying, or you may want to be on an aisle because you like to get up a lot. Maybe you are traveling with your kids, and want to be in the middle seat to referee. If you are trying to make a connector flight, you may want to be near the main exit so you can disembark as soon as possible. Whatever the reason, the more you travel, the more confident you become on your choice of seats, and so it is with music. Transposition, then, is akin to the act of choosing your seat on a plane and also sometimes, switching seats in mid-flight.
When I'm choosing the key for a piece these are some of my considerations:
Transposition (changing key) in mid-song is done for dramatic reasons. It's like SUDDENLY CHANGING TO ALL CAPS TO MAKE A POINT! It can be very effective, though if you do it too much it simply becomes annoying. When to have a key change is usually more the job of the composer, though on occasion, when I'm arranging something, I will throw in a key change because the song is kind of repetitive and I have become bored. With this song "Canada Ghost Lover", I transposed it through all 12 major keys as a learning exercise.
This music plane of ours has 24 seats. Twelve major and 12 minor. There are also blues scales, pentatonic, modes, chromatic and micro-tonal scales, but for this blog, I have checked them into the baggage section, so we can ignore their existence.
If you want to change seats (transpose) there are some easy moves and some difficult moves. Some will sound awkward as you climb over other passengers and only if you really want to draw attention to yourself do you choose those. Transposing to a relative minor is like switching to the seat beside you, pretty easy.
Transposing in the circle of 5ths, as I did with "Canada Ghost Lover," is probably the smoothest way and the most common. In circle of 5ths transposition, the dominant of the scale, becomes the tonic of the next scale and our ears adjust very naturally.
When I'm arranging a song that contains a key change or two, I have to transpose those key changes as well so the problems start multiplying and again you end up in a place where nobody is happy. As our music plane takes off, everyone hates their seats, the wifi doesn't work, the man in front has reclined into your lap, the kid behind starts randomly kicking your seat and you've seen the movie.
Follow Penny Will on Twitter: www.twitter.com/videosheetmusic