The dub chord from the Redux promo comes to mind here.
It’s a modified version of the “Dub Denker” instrument (factory preset), EQ’ed, with multiple multitap delays, digital filter and a convolution reverb for those reverse-sounding echoes.
Can be heard in the first and last seconds of the promo video, and in it’s raw form here:
https://soundcloud.com/renoise/redux-demo-dub-denker
Getting a good reverb going is always the trickiest part - I would stack a few ones, perhaps turn it into a separate doofer device
(hm, didn’t Achenar once post a video about stacking reverbs? Pretty sure he did…)
But most importantly, get a good basic sound going - I’m sure you can work out the rest by having some fun and experimenting.