Blissed is a sound-design/music app that uses simple additive synthesis effects to create ambient drone music and sounds.
It is based on Pure Data for the audio DSP.
To use it, you choose a scale, then assign some base frequencies, and then layer chords of sine waves. The chords work in pairs and you can modulate between them over a variable time window. Effects include chorus, distortion, reverb, and tremolo to make slowly shifting warm textures.
As with the previous version, I intend to share the source files but this time I’m tidying them up to make them more legible.
Some screenshots of the underlying Pure Data patch: