Key Notation

Rapid Evolution supports basic and advanced key notation, as well as key codes. It also supports the ability to notate keys which have been shifted from the standard tuning.

The general format is:

<root note> <scale type/mode> <shift>

For example:

Dm dorian +20

When no scale type is specified, major is assumed. The letter 'm' denotes a minor key. If a mode is specified (i.e. ionian, aeolian, dorian, phrygian, lydian, mixolydian, locrian) then the major/minor aspect can be implied. All the modes used can be classified as either major or minor.

When referring to major keys the letter of the tonic note is used, for example A major is just “A”. Minor keys are followed with an 'm', for example A minor is “Am”. There are a total of 24 fundamental keys:

• Major
  • A
  • A# or Bb
  • B
  • C
  • C# or Db
  • D
  • D# or Eb
  • E
  • F
  • F# or Gb
  • G
  • G# or Ab
• Minor
  • Am
  • A#m or Bbm
  • Bm
  • Cm
  • C#m or Dbm
  • Dm
  • D#m or Ebm
  • Em
  • Fm
  • F#m or Gbm
  • Gm
  • G#m or Abm

When reading/saying the keys, the # stands for “sharp” and b stands for “flat”. For example, Ebm would be read “E flat minor”. Since sharp means up 1 half-step and flat means down 1 half-step, it is possible for the same note/key to have 2 names, as you may have noticed:

• A# = Bb
• C# = Db
• D# = Eb
• F# = Gb
• G# = Ab

There is a system of key codes that is based off the circle of fifths which assists in harmonic mixing (from Harmonic-mixing.com):

This makes harmonic mixing easier because compatible keys are adjacent to each other on the wheel. While this makes remembering harmonic theory easier, keep in mind this is a simplified system and does not capture all of the details. One difficulty the wheel introduces is how the key code of a song changes as its speed is altered; i.e. speeding up a song in Am (8A) does not make it Em (9A) but rather, A#m (3A). This is equivalent to +7 keycodes. Therefore, the key code system only works when comparing songs of near equal BPMs. Note: this is one reason a program such as Rapid Evolution comes in handy, as it can easily determine whether songs are compatible after taking into consideration BPM difference.

In order to allow key codes to express more advanced modes, and to keep the simplicity that this system offers, a different set of letter codes is used in Rapid Evolution when showing advanced key information. Instead of using A and B to denote minor and major, respectively, the following letters will be used:

• A - Aeolian (natural minor)
• I - Ionian (normal major, normally B)
• D - Dorian
• P - Phrygian
• L - Lydian
• M - Mixolydian
• C - Locrian

Using this advanced notation, a song in 7D would be compatible with all 7's, as well as 6D + 8D, and reasonably compatible with the other 6's and 8's.

Sometimes songs have a key but are shifted from the standard pitch defined for notes (especially when recorded from vinyl). For example, the standard tuning for the A note just below middle C is defined as 440hz. However, if the song has been pitched up, these same A notes might be 450hz. These songs fall in between the standard keys, and are notated by their shift in cents from the closest key. A shift of 100 cents is equivalent to a half-step or semitone. For example, “Bm+50” is half way between Bm and Cm, and is the same as “Cm-50”. The built-in MIDI keyboard in Rapid Evolution contains a pitch shift slider which can be used to determine the exact shift of a song.