Can I use two minor scales in the same song? [duplicate]

Question

I've been composing a song, using the chord progression Am - G#° - Dm7/A - E (i - VII - iv - V), that is using the Harmonic minor scale.

The song has some melodies, that appear in different parts. The melodies are following the harmonic minor scale, but sometimes, I use G natural instead of G#.

The melodies that use G natural sound good to me, but I don't really know if this relationship between the two scales is correct practice.

Can I mix natural minor scale and harmonic minor scale in the same song?

Can I play G natural in a G#° chord?

EDIT: This is the song:

Thanks a lot for the help!

Answer 1

Can I mix the natural and harmonic minor scales in the same song?

Yes. It's helpful to think of "minor" as a collection of options rather than a single scale you have to commit to. Natural minor (Aeolian) is the "true" minor according to the key signature, and Harmonic minor and Melodic minor are representations of how composers modify Natural minor in their music.

So when you write "in minor", the "scale" available to you looks like this:

X:0
T:A minor note choices
K:none
M:none
L:1/4
"_1"A, "_2"B, "_b3"C "_4"D "_5"E "_b6"F "_6"^F "_b7"G "_7"^G A

A related question, with a related answer, came up here:
What scale is used with this descending bassline progression?

Can I play G, when a G#° chord is played?

Again, yes. It will be quite dissonant, but if that's the sound you want at a certain moment of the piece, then there's no reason to avoid it. As mentioned by @user1079505, you can think of G as Fx -- the #9 in an E7#9 chord. From that point of view, the voicing that will likely work best (with deference to your tastes as the composer) will be to put the G# below the D, and G (Fx) above.

In this example, the various options for B are given in parentheses.

X:0
T:Voicing G#dim against G
K:none
M:none
L:1/1
%%score (V1 V2 V3 V4 V5 V6)
[V:V1] "<("">)"B,
[V:V2] ^G
[V:V3] "<("">)"B
[V:V4] d
[V:V5] =g
[V:V6] "<("">)"b

Answer 2

1. If it sounds good, it's good
2. There is no rule forbidding you to change the scale in your song. In fact in jazz songs scales can change very often and they still can sound good and melodic.
3. To understand what's happening in your example, I'd point that G#o triad notes come from the E7 chord, which is a dominant in the key of Am. Dominant chords often use all sort of altered notes, to make them more dissonant, and increase strength of resolution to the tonic. In this case, I'd say "G" is in fact Fx, an augmented 9th of the E chord. Some frequently used scales which you may want to try are E half-whole (E F Fx G# A# B C# D), or E super-locrian (E F Fx G# A# C D) which typically permits adding the perfect fifth, B. But in the end, trust your ears!

Answer 3

In classical harmonic theory, there is only the minor mode. The three (or so) "scales" are common usages within that mode. Most pieces (songs, symphonies, etc.) use all forms of scale within the same piece. As noted by user107905, if it sounds good, it's good. Theory comes into play when you cannot find something good (and presents ideas that one will discover working alone; there's not enough time.)