Using multiple scales in one song

Question

Currently I am in the process of learning theory to be able to compose rap beats more efficiently and I have one question regarding (minor) scales.

I know the formulas for natural, minor and harmonic scales and also the history of those scales.

However how are these scales being actually used in modern music?

Some time ago I started building songs, say just around the harmonic minor...but the result was really weird, sonically speaking.

So my question is: Can you use multiple scales, or types of scales in one composition?

Say, use c# harmonic minor for the chords and in the same song use the melodic minor just for the melody?

I know that you can basically do anything you want and this is only theory...but still. Is there something of a rule of thumb or guideline as to how to employ those scales?

Answer 1

When a piece is in a minor key, it's commonplace to mix natural, harmonic and melodic minor scale notes. After all, the descending (classical) melodic IS the natural minor, there's a raised leading note in melodic and harmonic, so the only real debatable note/s are the 6th - as in A minor, either using F or/and F#. Dependent as to where the melody (and harmony) are, or are going, either could well fit, and be technically correct into the bargain! It's the oft quoted - if it sounds good, it usually is.

Answer 2

Todd is right, and I'm just going to expand a bit, to help you be more comfortable with this.

The three variants of minor are not really separate entities. They work fluidly together in exactly the way you have proposed. One way of looking at the minor key is to say, let's start with natural minor. What little adjustments do we need to make, so that we are pleased with the results? Well, we are often going to want a major chord for our dominant, because we like that V - i progression. In our melody, we are often going to want to raise the 6th and the 7th when we are leading to the tonic because we like leading to the tonic that way.

Experiment and feel free to move fluidly among the three types of minor, as you like.

Answer 3

This may be a sweeping over-generalization -- there are exceptions to everything -- but most pop music, rock and blues, stays in one key and uses the basic three chords in that key, which means the only scale notes used are the 7 notes in that key.

Commonly, songs can use two keys: the main key, and then a modulation to a key that is a 5th apart. For instance, starting a song in C major but having a section that goes to G major (G is the 5 chord in the key of C) and then returning to C at the end. So the G major section of the song would use the G major scale, which has a different center, and one note different than those in the C scale (the note F# instead of F natural).

However, jazz uses a lot more chords, and more complex chords at that -- chords that don't stay in one key all the time. Jazz can get so complicated that each chord has its own different scale that goes with it. A bebop jazz soloist knows the particular scale that goes with each different chord, and as he improvises a solo, he knows to switch from scale to scale as he moves through the chord progression. This is an extremely advanced technique in playing melodies and licks, as you might imagine. Yet experienced jazz musicians just make it up as they go along very fast.

This sort of thing can be found in some R&B and funk, too.

So if your rap beats sample jazz chord licks, then your topline could use some pretty out-there changes in notes and scales.

If you want to learn more about this, take some lessons in jazz chords and soloing on piano or guitar.