This is a cross-post from a thread on KVR where I answered this question. Full thread can be found here, your thoughts are welcome as well, of course.
"Diffuse" effect implies that time is no longer very defined.
So, anything that will "prolong, repeat" your sound in very shorts chunks of time will be heard as diffusing. Particularly if applied to high frequencies (HF hereafter) — mids and lows are not that time-defined anyway. We can use a very short and not particularly diffused reverb (there, diffusion stands for anti-definition, which we don't need). It also can be a repeated signal with modulations (like auto-tune, chorus, slow barely unnoticeable flanger -- try what you'd like best) which then is delayed very-very slightly (Voxengo Sound Delay is great for that, as it can specify very short chunks of time in ms and samples; free, also).
Once again, we're not going for a delay-like effect here, we're adding tens ms of delay, tops, to achieve an illusion of a solid, but "watery" sound.
I think that the illusion can be also enhanced by degrading a mid channel (maybe just volume with Voxengo MSED, maybe with any M/S equaliser), by slightly emphasizing a side channel (short reverbs, diffused this time, but rather thick in terms of volume envelope) and probably by compressing this together and laying some kind of texture on top (like maybe volume-automated filtered tape hiss, maybe crackles/sparkles — tiny almost undecipherable things to add variation in stereo and HF). Proximity can help with finding the right balance of volume, width and frequencies for a particular track.
You might also like to look at Thesis2, though the effect could be much wilder than you need.
Every software I've noted is free, just gets your brain and hands to work it.
Edit: Speaking of Burial, I'm very sure that you can achieve same kind of effect using Waves SoundShifter, a pitch-shifter that works in real time. Can sound beautiful as hell.
Submitted February 16, 2017 at 03:10PM by Vospi https://www.reddit.com/r/edmproduction/comments/5ugq6i/effect_that_diffuse_a_sound_explanation/?utm_source=ifttt