Here’s a method to get that crunk/trap bass working with your Roland TR-808 drum machine. You know, like that fat Wiz Khalifa track. In brief, the whole point is the get the attack from a kick and some tonality in the following sub-bass boom. And while they’re on the same frequency, you need to make ‘em play along.
Upload an accented 808 kick drum sample with little decay (meaning a dry, short kick without any boom to it) to your sampler.
Get ya sub-bass on. Program it to hit on the same notes as the kick.
Now, the trick is in the Amplitude Envelope of your synth generating the sub-bass: a) slightly adjust the Attack so it doesn’t clash with the kick, b) set the Decay to around 650 ms, c) bring Sustain all down to the bottom and d) raise the Release to around 2,6 s.
You may adjust these numbers so you get the desired sound, but leave the Sustain level to null.
That’s it. I didn’t invent this, I got it Dorincourt, and he didn’t come up with it either. It’s been around for ages. Still, it’s not common knowledge.