- most of electronic music is in minor scale so an "easy" way would be to measure note frequencies and assign the corresponding minor key
- as you know every minor key has corresponding major key. For example Cmaj has exactly same frequencies as Amin. So which key should you assign?
- then again when you consider that every key has a lot of modes, then there is the harmonic and melodic scales etc... it gets even more complicated
- one typical example: goa trance. A lot of tunes are in E-phrygian which has same keys as C-maj or A-min but the most common note is E (and most common bass note is E). So what would be the official key definition for such a tune?
- is it likely that and automatic key recognition software can find the right key if mode is something else than minor
- what makes it even more complicated is that in some situations DJ might care more about the notes that do/dont play in the tune, in other situations DJ-might care more about the root/bass note.
- So lets assume one tune is in A-minor. You could mix harmonically to E-phrygian (if I have understood correct) because all notes stay the same. But bass note will change from A to E. So one scenario of mixing, be sure that all notes stay the same
- another scenario of mixing, be sure that root note stays the same, so you could mix from E-phrygian to E-minor or E-dorian or whatever...
