Tutorial EDM Drones

I came across a tutorial for creating EDM drones (Example of a drone; you can make one using different pitches, though.). I'm sure it's not the only way, and may not even be the best way, but it is very approachable and customizable--it can be done (possibly with varying degrees of success) with effects/instruments that your DAW probably comes with, and it has MIDI notes as its foundation, so you can directly control how it sounds.

Here's a link to the Alex Rome tutorial: link.

As you'll see in the tutorial, a drone is usually constructed around a song's tonic note and is used to fill in the song's background.

Making a Drone
Alex does basically the following to construct his drone:

1. Lay down a series of 8th notes at the tonic pitch
2. Raise every second 8th note either 3 semitones or 7 semitones, as you prefer. You could also lower the notes instead, or experiment with raising/lowering by a different number of semitones.
3. In the synth you're using, select a saw-shaped wave. (He doesn't say to do this, but it seems to be what his synth is using. Different wave shapes would make somewhat different-sounding results.)
4. Turn up the number of voices to taste. (In his Serum synth, this setting was called "unison.") He turns his up to 13. As with any of these instructions, you can experiment to get a different sound, though. If your synth doesn't have a changeable number of voices, I think you could also use a chorusing effect plugin. Also, adjust the amount of detuning between the voices (i.e., the amount of difference between the voices in the pitches they use) to your preference.
5. Turn down sustain and decay until you get a plucked sound. His sustain was negative infinity and decay was 155 ms. Again, you can set these to taste.
6. Alex also raised the pitch of his synth by an octave. You could do that if you wanted, or not. You could also simply change the MIDI notes if you didn't have that setting available.
7. Apply reverb to the synth. Turn the mix setting up so that you get more of a wet sound (i.e., so that the sound of the reverb effect itself is very prominent). Turn up the decay and size (time) of the reverb to taste.
8. If you wish, you can apply an EQ filter to filter off some of the high end sound.
9. Optionally, you can add a tremolo/autopan effect to automatically pan the sound of the drone between left and right. He uses a rate of 1 bar and a depth of 60%.

As I mentioned, Alex Rome uses Serum to create his drone in the tutorial, although he says any synth could be used. I've done it myself with Matt Tytel's free Vital synth, although I had to play with the reverb/a few other settings a little differently from how the tutorial did, possibly because the synth/reverb were different.

Altering a Drone During a Song
The tutorial mentions that a drone is usually kept constant throughout a song, with the idea being that changing something that is perceived as being fundamental/constant can end up being jarring/confusing to people. However, near the beginning, you'll see where Alex has used some kind of automation to change how his drone sounds at one point in his song, so this guidance is open to creativity/taste.

In that vein, I personally experimented with changing the pitch of my drone. There are 3 ways I considered doing this:

1. Changing the MIDI notes
2. Pitchbending
3. Using a pitch-changing effect plugin

All of these potentially could be useful, depending on the effect you want. The issue I foresee with the MIDI notes/pitchbending is that the heart of this drone is reverb, with each note played by the synth being given a reverb echo at that particular pitch in order to create what you might call a virtual chord. If you suddenly use different MIDI notes or pitchbend the original ones, you'll end up with a stack of reverbed upward or downward-trending pitches. That could end up sounding very busy and noisy while the pitch transition is going on, especially with how long the reverb has been set to last.

With that in mind, I've found the pitch-changing effect plugin to work well. I personally experimented with Waves' ElastiquePitch. By putting the plugin onto your drone as the last item in its effect chain (or at least late enough; it would go after the tremolo/autopan effect from the tutorial), the plugin gains control of the entire sound, both the original MIDI notes and the reverb. This means there are no lingering/stacking echoes of past MIDI notes at old pitches, so the entire drone can be pulled up/down in pitch together.