A musical key defines the tonal center of a song and the notes that sound most stable within it.
Understanding keys helps DJs anticipate how songs may sound together during transitions.
Notation
Keys in music are generally notated with a letter (A-G) and a mode. For example A major (abbreviated A), G# minor (abbreviated G#m), or Eb.
The letter refers to which musical note (A-G) acts as the root or tonal center of the song. Generally, music is structured around this set note which it returns to over and over and which other notes feel “drawn” to by musical (and cultural) convention.
Music can also change this root during the song note in something called a key change.
The mode refers to which sequence of other notes (out of all available notes) the song generally chooses to stick to. This helps set a consistent tone for the song (as certain sequences of notes feel happy, while others feel sad or unstable) and keeps the song from feeling chaotic.
The most modes are Major and Minor.
Put together, an example like Eb minor means:
- Eb (E flat major) is the root of the song. This will sound like tonal “home base”.
- The song uses the set of notes in the major scale.