Huge "Deep House" Bassline

[Tenova]

Hey all,

I'm wondering what the general lowdown is on how Oliver Heldens created his bassline here. NOT the lead, there are a million tutorials on how to create his iconic Gecko lead, but the very Deep, overwhelming bassline that's in the below video.

It comes in around 29-30 seconds, linked below.

https://www.youtube.com/watch?feature=player_detailpage&v=jjx2oc2NRzA#t=29

 

[scrapheaper]

Your starting point is a sine or very lowpassed other wave with portamento.
Probably with another sine an octave down for sub, but I haven't got good headphones atm so I can't tell about the sub.