Not sure its relevant but check out some music by Rhythm & Sound - they often feature a very present noise floor that definitely contributes to the feel/vibe of it....
you can hear it on this track despite youtubes crap compression
but seek out the vinyl of any of their tracks - its beautiful...
YouTube - rhythm & sound w/ tikiman - jah rule
sounds to me like analogue processing noise floor, which sometimes pumps in rhythm to the beat.... theres been lots of speculation about how they make their music, as they are not forthcoming on any technical details...
Rhythm & Sound Rhythm & Sound Discography at Discogs Basic Channel - Wikipedia, the free encyclopedia