If you write out a song or have music for a song in a certain key
, your odds are pretty good that your singers won't be able to sing it in that key - unless of course you already have a good idea of the vocal ranges and preferred keys of your singers. What you will need to do then is transpose the song to a different key.
For example, let's say that you have a song in the key of "G" with this chord progression:
G Em C D G Em C D D F C D
To your annoyance, you then find that your singer or singers cannot sing it in that key, but they think that they can do it in the key of "Bb". So, you will have to transpose this chord progression to the key of "Bb". This can be done quickly and easily if you use the Chromatic Scale. Here's how you would do it:
First, write out the Chromatic Scale starting from the key that you already have the song in. That would be "G".
G G# A A# B C C# D D# E F F# G (The key of G is a sharp key)
Then underneath it, write out another Chromatic Scale starting from the key that you NEED it to be. That would be "Bb" (a flat key).
G G# A A# B C C# D D# E F F# G
Bb B C Db D Eb E F Gb G Ab A Bb
Now all you have to do is to do direct substitution from top to bottom and you will have:
G Em C D G Em C D D F C D
Bb Gm Eb F Bb Gm Eb F F Ab Eb F
And there you go. Your singers will now be able to sing the song.