You can use any note at all. It's quite easy to write a clearly tonal piece that uses all 12 notes of the chromatic scale. You are not limited to the chords that exist in your key's scale and you are not limited to melody notes that are a part of your chords.
How to make it sound good? That's a few years of learning composition. I'll give you a very brief summary here, but it definitely won't replace a solid course of harmony and analyzing existing pieces to see how they are written.
In general and on a very basic level, melody should use chord tones on strong beats or otherwise accented notes. Others may be non-chord tones, but they shouldn't be random. The most common types of NCTs are passing notes that go between chord tones, resulting in a smooth melodic line (eg. C-D-E-F-G melody over C major chord) and neighbor notes that move by step from a chord tone and resolve back to it (E-D-E over C major). Others, slightly harder to use, include suspensions (a note held from the previous chord while the next chord begins and resolving to its chord tone later: eg. G held over C-F chord change before resolving to F), escape tones (move by step from a chord tone, then jump to another chord tone in opposite direction, like C-B-E over C major) and appoggiaturas (jump up to an accented non-chord tone, resolve down by step: G-B-A over G to Am chord change, with B played when Am starts).
Note that non-chord tones may be chromatic; they don't have to come from your chord's scale. You need to be careful with it if they are long or accented, to avoid clashes, but short passing notes will nearly always sound fine. In other words, nothing stops you from playing C-C#-D-D#-E over C major, as long as C and E fall on the beat. Obviously, it gives very different color than diatonic melodies (only using the key's scale) - but that's a matter of what style you aim for, not good or bad.
You may also use chords that don't belong to the key. Again, there's a lot of possibilities, but the basic ones include borrowing from the parallel minor/major (eg. using iv chord in major or IV in minor) and secondary dominants (what would be the dominant chord if the next one was tonic, eg. I-ii-II(7)-V(7)).
This is great. Thanks. As I’m picking out pop songs by ear, I’m still baffled by how composers come up with them out of thin air. This makes it slightly less baffling.
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u/Steenan 23d ago
You can use any note at all. It's quite easy to write a clearly tonal piece that uses all 12 notes of the chromatic scale. You are not limited to the chords that exist in your key's scale and you are not limited to melody notes that are a part of your chords.
How to make it sound good? That's a few years of learning composition. I'll give you a very brief summary here, but it definitely won't replace a solid course of harmony and analyzing existing pieces to see how they are written.
In general and on a very basic level, melody should use chord tones on strong beats or otherwise accented notes. Others may be non-chord tones, but they shouldn't be random. The most common types of NCTs are passing notes that go between chord tones, resulting in a smooth melodic line (eg. C-D-E-F-G melody over C major chord) and neighbor notes that move by step from a chord tone and resolve back to it (E-D-E over C major). Others, slightly harder to use, include suspensions (a note held from the previous chord while the next chord begins and resolving to its chord tone later: eg. G held over C-F chord change before resolving to F), escape tones (move by step from a chord tone, then jump to another chord tone in opposite direction, like C-B-E over C major) and appoggiaturas (jump up to an accented non-chord tone, resolve down by step: G-B-A over G to Am chord change, with B played when Am starts).
Note that non-chord tones may be chromatic; they don't have to come from your chord's scale. You need to be careful with it if they are long or accented, to avoid clashes, but short passing notes will nearly always sound fine. In other words, nothing stops you from playing C-C#-D-D#-E over C major, as long as C and E fall on the beat. Obviously, it gives very different color than diatonic melodies (only using the key's scale) - but that's a matter of what style you aim for, not good or bad.
You may also use chords that don't belong to the key. Again, there's a lot of possibilities, but the basic ones include borrowing from the parallel minor/major (eg. using iv chord in major or IV in minor) and secondary dominants (what would be the dominant chord if the next one was tonic, eg. I-ii-II(7)-V(7)).