I’ve been listening to this chasing shadows tunes a lot recently :
http://www.youtube.com/watch?v=JzX5FlXVbx4
http://www.youtube.com/v/JzX5FlXVbx4&hl=nl&fs=1
I’m quite good with making fatt distorted basses , I normally have
a couple of detuned saws , maybe a square as well , going though
all the usual processing , Distortion , flange , comp ect …
But I’ve never been able to make anything quite like they do .
Any ideas/tips on how they get there sound would be apreciated .
Sounds indeed like distorted saw/square layered with a sub… nothing really special, maybe some octave-shifts here and there… Trick is resampling all the layers of bass seperately, I guess… And resampling! And resampling again! 
yeah i thought simalar on the resampling , but even when i try that (maybe i’m just doing it wrong I still can’t get the depth that they achive .
i just found this article on pendulums bass sound and he seems to think it’s the way they get it to fit in the mix , using quieter sounds at the start and having a very loud bass kick in and also multiband comps . It’s the multi band comp bit that interests me and how you use em.
fm synthesis… metallic sounds !!
that’s what I start off with, something with lots of midrange
Easy route, sample their bass, filter it, then re-add distortion, effects etc…