Experiment with the OSC 1 Feedback. It’s savage
Modulate the feedback with the OSC 2 AM and Sync
Add plenty of Drive and shape with the Filters and LFOs
Here’s a brief experiment.
SoundCloud - Hear the world’s sounds
Not quite droning sounds. But kind of. There is only one trig used in this. But smoother textures can easily achieved with slower, smoother LFO and ENV settings