This is a simple recipe for making a growly dubstep-style bass using Native Instruments FM8. The primary reference for this is SeamlessR – How To Bass 50: FM From The Ground Up Using FM8.
Start with one carrier wave going to output at 100%
Then a second wave will modulate the carrier. This is the one we will automate or control to do the growl effect later.
There is one last modulator that is critical. The third wave should modulate the second wave by about 10-12% at a ratio of 32. Once set you can leave it.
Everything is set now. To create the growl effect, adjust the level of the second wave (E) and how much it modulates the main carrier.
You should now be able to create a growly dubstep style bass using FM8 or any other FM synth. If you want to test it out, you can download the FM8 preset.