I would say effects. He plays just single notes with a pick.
But without looking at the clip i could definitely hear a bass, and a guitar. But where is the guitar. I've found this. http://www.youtube.com/watch?v=33lnW1qDehc
That's live and there is just no guitar.
"Benji must get through 4 or 5 drum kits a week with the intensity of his playing and bassist/ vocalist Michael runs through guitar and bass amps as well as an array of aftereffects to contriubute to the massive sound."
So that's the trick.
My guess is that the recording you send was probably with overdubbing as well. Cause i could hear the bass playing different notes as the 'guitar' sound. In the live clip you could hear the 'guitar' sound doing the same as the bass sound.
So that's probably guitar amps being overdriven, and maybe and octave up along the way as well.
my 2 cents