How to handle songs whose scales are neither major or minor in harmonic mixing?

Question

Harmonic mixing typically relies on the circle of fifths, often renamed as the "Camelot wheel" in the context of harmonic mixing. However, that circle/wheel only contains two scales: major and minor. How should one handle songs whose scales are neither major or minor in harmonic mixing (Dorian, Phrygian, Lydian, etc.)?

Answer 1

The Camelot Wheel groups major and minor scales together by giving them the letters B and A respectively, and relative scales together with the same number term (1–12).

For example, the scales that have a key signatures without any sharps or flats: C major (Ionian) is 8B, and A minor (Aeolian) 8A.
By this logic, D Dorian (also without any sharps or flats) should be some kind of 8, say 8D. But this would be an extension to the Camelot system — if you’re trying to use some DJ software it’s probably not going to understand 8D.

Another way to think about it, would be that D Dorian is really just a special type of D minor (with a major 6th), so it should be grouped as 7A along with D Aeolian (natural minor), D Phrygian, and D Locrian. Whereas the three types of D major scale: D Mixolydian, D Ionian, and D Lydian, should all be grouped as 10B.
This would also make it trivial to group the more exotic scales (that would otherwise be un-groupable because they aren’t really relative to any major scale), such as Hungarian minor (with a minor 3rd and 6th, major 7th, and augmented 4th), etc.

---

The thing about scales/modes is that they can be used in a variety of different ways. It could be just the melody that is using the scale, it could be just the harmony, it could be both, or perhaps something more complicated than that. How your piece is using the scale will be relevant to how you should group it. If you’re using the Camelot Wheel to group together pieces with a similar harmony then you should probably stick to the major vs minor grouping.

Answer 2

What is harmonic mixing

There seem to be two kinds of practices that can be called harmonic mixing:

• (1) common tonic mixing: keep the same key i.e. tonic and probably also the third (major/minor), or
• (2) common pitch set mixing: mix things that are restricted to the same set of pitches, regardless of their tonics, as explained in this Franck Dernoncourt's answer.

Let's see what "harmonic mixing" is according to Wikipedia https://en.wikipedia.org/wiki/Harmonic_mixing

The primary goal of harmonic mixing is to create a smooth transition between songs. Songs in the same key do not generate a dissonant tone when mixed. This technique enables DJs to create a harmonious and consonant mashup with any music genre.

So this is clearly about mixing in the first meaning. But what does it say about keys again?

Songs in the same key do not generate a dissonant tone when mixed?

This approximation helps DJs get their work done, but if you go into musician land and actually find out how things work (as you have now done), you'll have to decide that the claim is not really true. Key is about tonic, not pitch sets.

To falsify the statement "Songs in the same key do not generate a dissonant tone when mixed", we can take any song that has chromatic alterations such as secondary dominants, tritone substitutions, dominants in a minor key, or just colorful chords, and we'll see that such a song isn't even mix-compatible with itself. There WILL BE dissonant tones when mixed.

For example the chorus of "Everybody Dance" by Chic, which goes like this:

Cm    Ab       Bb     
Everybody dance, do-do-do
          Ab      F/A       Ab/Bb
Clap your hands, clap your hands

The F/A chord will create a clash when mixed over any part of the same song that uses an Ab note, such as part of the previous line. And the song does not modulate, a chromatic alteration is not a key change.

Another example: the original non-remixed version "Sexbomb" by Tom Jones. It's in G# minor (before a modulation to C minor in the end-part), and it has C# or C#7 dominant chords, and those chords will generate a dissonant clash when mixed over many other sections of the song. Maybe that's the reason why there are various other versions of the tune where the chromatic alterations have been removed, and C# chords replaced with C#m chords?

What the Wikipedia page really tries to say is: mixing songs with a common key will be much less likely to create dissonant pitch clashes than mixing songs with different keys.

Common tonic mixing and modes

In-key (common-tonic) mixing would treat snippets of music in, say, G Dorian and G Aeolian modes as mixable in some way. Or if you like, even G Ionian. And of course traditional in-key music with chromatic alterations of scale degrees like secondary dominants, diminished sevenths, tritone substitutions etc. Mixing audio from modes with the same root/tonic but different scales or the same key center but with chromatic alterations, so that they play at the same time can clearly create pitch clashes (despite what Wikipedia says), so it's better to do the mixing more like switching between the samples or songs. If you do a cross-fade, the longer it takes, the bigger the risk of something clashing, even if the tunes are in a common key. If you do it quickly, or if you're just lucky, you will get a certain feeling of modal change or mixture, but without chaos. If the key center stays the same, there will be a feeling of continuity. As long as clashing pitches aren't played completely simultaneously, chaotic feelings are avoided as well. (There are some exceptions to this, for example you can play C minor pentatonic lines over C major, and the clashes can actually sound really good)

In addition to plain old DJ'ing where you play track after track, a relevant use-case for in-key mixing could be techno/house/dance where you want to keep your kick drum and maybe bass rumble tuned to the tonic. For example, G, for 909 kicks. If your kick is hammering on G, it's a musical choice to use a track in G something, for your French house mix.

Common pitch sets

Then the common-pitch-sets mixing. (I deliberately and specifically do not say "common scales" because conceptually, a scale has a root note, and if the root is different, it's not the same scale. If you want to, you can forget this distinction and just talk about scales, but it may cause confusion if it's not clear when you mean that the roots are the same too, and when you don't mean that.) Here the idea is to find things that can be played really simultaneously, without creating pitch clashes. If you have a backing chords loop which uses, say, Em7 and Am7 chords, it is pitch-set-mixable with the C major scale and all its modes, and the G major scale and all its modes. To find a melody loop that does not clash with the backing chord loop, you could take anything that only uses the pitches in any of those scales. Depending on what the root or center of the melody happens to be, you'll get different harmonic feels as a result.

For example, if your backing chords are Am7 and Em7, you could use a melody line that's in D Mixolydian. Maybe an interesting combination?

To sum this up, I'd say that common tonic (in-key) mixing might be more useful in DJ'ing where you switch from song to song. And common-pitch-set mixing would be more useful for producing beats, mash-ups and other things where you handle musical elements on a lower level than entire songs.

Answer 3

As a complement to Elements In Space's answer, I found two webpages advising to look which notes the scales contain when using harmonic mixing:

https://hiphopdatabase.fandom.com/wiki/Harmonic_mixing:

Which notes are in the scale is much more important than which is the tonic. [...]. For example F lydian and B locrian contain the same notes as A minor, so these should be compatible, and slightly less with D minor and E minor.

which is echoed by https://www.dogsonacid.com/threads/harmonic-mixing-with-modes.823401/page-2:

E phrygian has the same notes as C major but uses E for root. So Eb phrygian should have the same notes as B major but using Eb for root. Therefore I would say using the traditional harmonic mixing rules for matching B major should sound good with Eb phygian.