JPhelpz 'Trill' Synth

[OhGee]

https://soundcloud.com/jphelpz/jphelpz- ... iew#t=0:38

Looking to make this gnarly bass.
Sounds like a square wave going through a band reject, but I can't seem to get it.

Anyone care to help me with this?

I can post some tutorials I've made in Massive (I know, I know..)