the Harmonic minor scale has a very specific flavor to it.
when you learn a new scale you should also learn when/why you should use that scale.
easy explanation: often in any minor key, the 5th degree chord is changed by the guitar player to a major chord (or as a 7th chord) instead of the minor chord.
why?
bc it just 'sounds' more interesting. it sounds more 'convincing'.
when this happens,
you can play the harmonic minor scale instead of the usual natural minor or the pentatonic minor scale.
its easy to recognize when this happens bc it has a really specific flavor to it.
try it out yourself.
play a chord progression in any minor scale and replace the 5th chord degree with a major chord instead.
I - VII - V - IV
instead of
I - VII - v - IV
so for example,
in the key of A minor (A,B,C,D,E,F,G), if we follow the key, the 5th chord degree would be E MINOR.
but often what you hear alot are people replacing that E MINOR chord in the key of A minor (or nay minor key) with an E MAJOR chord instead.
so you hear a typical major sound and during this moment, on the 5 chord in a minor key, its great to pull out that harmonic minor scale when the 5 chord is played as a major chord (or a dominant 7th chord as well).
----
long explanation: when you play in a MINOR key, lets use A MINOR as an example again.
we can construct chords from the minor scale,
resulting with the following chords, in the key of A MINOR:
A minor / B Diminished / C Major / D minor / E minor / F Major / G Major
(these are the same chords that we use in the key of C major btw)
so a chord pattern we hear alot is:
A minor > G > F > E then back to A minor as the chord progression repeats
I - VII - V - IV
instead of
I - VII - v - IV
that E to Am chord resolution is something that we hear often, (the 5 back to the 1 chord is quite common).
but if you look at the chords from A minor scale, we see that the E major chord should TECHNICALLY be an E minor chord.
so since the minor 3rd interval within that E chord is a G-note (which is the 7th note from the A minor scale)
but remember, in alot of songs, the 5 chord is played as a major chord instead bc it just sounds better.
simply bc the chord just 'sounds' as though it truly wants to resolve back to the 1 chord.
try it out yourself.
there is a powerful resolution when you hear the E major resolve back to the A minor chord.
then compare that and play a chord progression with E minor resolving back to the A minor chord.
it sounds less strong.
so how does this all translate to the way we should play
well that depends on how much you want to emphasize that E major sound instead of the E minor sound.
so the G note from the E minor chord becomes a G# when you play the E major chord instead.
remember that the 7th note in the A minor scale is a G.
therefore if youre playing a solo, for example, then you should be playing that G#-note to accompany the E major chord, right?
but that G# isnt present in the natural Aminor scale, so that is an example of when you would play the Harmonic minor.
simply raising the 7th note of the minor scale by a half-step. that is the Harmonic minor scale.
Functions of Harmonic minor: 1 - 2- b3 - 4 - 5 -b6 - 7
technically you can play the AMINOR pentatonic over the progression too if you want but if you want to stress that E MAJOR chord and really let it shine then you should try to play A HARMONIC minor of that final chord in the progression.
that goes for an MINOR chord progression where the 5 chord is played as a MAJOR chord, which happens quite often.