The effect appears between ~2:26 and 2:33 on the 303 bass in this track:
http://www.youtube.com/watch?v=3ZtUuHujB20

I have no clue how to do it, and since Im not that into EDM I dont even know hoe to call this effect...

Hope anybody could help *yes*

 

It sounds like he progressively boosts the resonance on the bass. I don't know if you know but resonance is emphasis at the filter cutoff point making those frequencies more prominent. It also reduces the lower frequencies of the bass.

 

lowpassfilter close and open.

 

It could be that too but it seems like he boosts the resonance because there are less low frequency elements and it seems more biting beyond what filter automation could accomplish.

 

Automation of the resonance. As Catalyst said the filter cutoff point is exaggerated when you boost the resonance and being that the filter is already being modulated via an envelope, lfo or step sequence I doubt he's opening the filter to achieve this. Open any 303/acid style bass patch if you don't know how to program one and try this yourself. You'll see you don't need to touch the cutoff to get exactly the same result. Also, the bass is most likely being distorted.

Very lazy but you get the idea.

 

Saw wave + filter cutoff + reso. Sounds like acid bass line.

 

love that sound - since 1997

 

You can try:

AudioRealism Bass Line 2 or D16 Phoscyon (for me the best 303 emulators)

Play with filter cutoff/resonance and use overdrive/distortion.

Enjoy.

 

+1
Awesome synths. *yes*