I'm yet to make anything that would be considered drone, I think it is very easy to add to much. I've used a program called paulstretch for stretching samples to ridiculous lengths which might be helpful - its easy to find via google
Who's into Reaktor here? There's a new plug-in on the upgrade which is pretty mucg a drone machine thing that is sample-based, it has some nice sounds but then again it's good to tweak it or replace the sample for a unique magic sound
Type knob = dTape. (this gives the sound a nice warble)
Time knob = 6 O'clock.
Repeats knob = 3 O'clock.
Mix knob = 4 O'clock.
Filter & Grit knobs = set all the way to the left.
Speed & Depth knobs = set to taste. (this is the amount and speed of the tape warble)
Mode knob = "modulation"
E. level knob = 4 O'clock.
Tone knob = 9 O'clock.
Time knob = 5 O'clock.
I use my volume pedal to swell in the note / chord that I want and then volume down whenever I feel like and let the delay and reverb trail out. Sometimes I will also hold down the delay button on my Timeline pedal. This will hold the delay out a create a swelling effect on that single note / chord. Then when I let off the button the delays will trail out nicely.
Once I have the sound recorded the way I like, I will edit it in Abelton accordingly...adding more reverb and delay and whatever else I feel like doing to it.
I think I most prefer a method another poster mentioned, taking samples(I have a field recorder, which is great for this), and time-stretching it to oblivion. I made the background for a sweet song doing this with a sample of some birds chirping in the morning for like 15 seconds while I was walking to work.
Another favorite method is just getting something dissonant, whether it's a 2nd interval on my uKorg(or otherwise), or using some sort of pitching effect and messing with cents of difference(not semitonal).
I think in all cases it's about what you do with the FX.
I may mess with chords, but if I do it's probably when I'm mangling the output of my uKorg, which will have the release all the way up, kind of just jam these out so idk how to describe the chordal quality, sorry.
Single notes work too, but I think in these cases more careful attention to excellent FXing will be in order.