Arpeggio theory and chord sequences

Question

I can play a little piano by ear and have always been fascinated by arpeggios, particularly in electronic music.

The following notes played as a chord sound 'good' to me and I'd like to compose a passage of music which incorporates these notes (or maybe more accurately the distances?) but then moves them in a chord sequence.

(D G) (A# D F G) (brackets indicate left hand and right hand)

What chords would go well with this and why? (in terms of music theory) I'm more inclined towards jazzy sounding and minor chords than bright major chords. I'll be generating the arpeggios in steps

Here's an example of some arpeggio based music which has inspired me to explore this:

Marc Melia Arpeggios #1

This image shows a combination of an arpeggiator and chord device which works by adding steps in semitones to a root note and then applies a style such as 'converge and diverge' or 'Thumb UpDown'.

Answer 1

The notes in your question form a G minor seventh (Gm7) arpeggio. Your voicing doesn't have the root note G as a bass note, but the fifth (D). The 'formula' for a minor seventh chord is

root - minor third - perfect fifth - minor seventh

(all counted from the root), which for a Gm7 chord gives

G Bb D F

(you used the enharmonically equivalent A# instead of the Bb, but it is a Bb because it's a minor third, not an augmented second).

Instead of (wrongly) trying to tell you what would be "correct", I'd suggest to use your ears to shift that arpeggio around, maybe changing the intervals slightly as you move around. In this way you can compose freely without being restricted by some theoretical knowledge which is often misunderstood as prescriptive rules.

Answer 2

You are definitely playing a Gm7 chord. The notes are G, Bb, D, F, and you have inverted (rearranged) their order. Chords that would sound good alongside Gm7 would include all chords that are in the same scale. So what scale are you playing?

Well, it's musically ambiguous--Gm7 belongs to many scales--and it's up to you as the composer if you want to resolve the ambiguity or not. Since you're only playing 4 unique notes (they're technically called "pitch classes"), if you provide some other notes, you can resolve the harmonic ambiguity if you want.

If we consider only the set of diatonic scales (the normal scales used 99% of the time in pop and classical music), Gm7 belongs to either F major, B flat major, or E flat major.

Adding notes/chords from the E flat major scale on top of the notes you're playing will generally cause the arpeggio to sound darker. This is because they would make Gm7 sound like it is in the Phrygian mode which is dark and mysterious sounding. Try adding chords with the notes Ab or Eb and you'll see what I mean.

Adding notes or chords from F major will likely make the song sound brighter, giving it a Dorian feel. It could sound like Carlos Santana or Fela Kuti.

Lastly, adding notes in B flat major are more likely to have a neutral impact. It will just sound like plain, vanilla Aeolian minor scale. (see Darude's Sandstorm)

If you want to get stranger sounds, you can also add notes or move to chords from G octatonic (by which I mean G G# A# B C# D E F) and F melodic minor scales.

By sticking to these 5 scales you can express a broad range of feelings and they should all sound pretty good when arpeggiated. Minor 7 chords (like Gm7) are among the most versatile of all chords with 4 notes. There's a reason minor 7 chords are so widely used in electronic music: they sound good in lots of different scales and contexts.