Video showing an automated bass sound that changes throughout the track. Cutoff, Resonance, Distortion Drive, and Bit Reduction are mapped as parameters to the control panel in the bottom of the screen, and hence show up as parameters inside the host application and can be automated (in this case I used Ableton Live). Then it's just a matter over tweaking and recording those parameters to taste while playing the song. The video shows the playback afterwards.
If you want something 303'ish, perhaps with a slightly different sound to it, then it's possible inside KarmaFX Synth. The video shows tweaking such a bassline using a saw osc to connected to a filter with some fast exp envelopes assigned to cutoff and amplifier. Porta/Legato is added to get the familiar slide, and distortion, reverb and delay to add some extra sparkle.
A simple dubsteppy bassline with cutoff frequency wobble and distortion.The bass consists of two square oscillators, slightly detuned and placed an octave apart. A miditrig module set in velocity mode is hooked up to the lfo rate that controls cutoff, such that the velocity in the track can control the wobble frequency. The bass also has portamento and some reberb+delay.
An advanced tutorial on how to use the compressor module to reduce frequency overlaps in a kick and bass sequence, by routing the kick sound into the sidechain of the compressor thus compressing the bass when the kick is heard.
Video showing how to do fast frequency sweeps with lfo control, to achieve that squeaky high frequency modulated lead sound, well known from access virus and psytrance music. First a good saw lead with highpass filter is created and some phase modulation. Then an LFO is hooked up to the frequency module, which gives full control over frequency. Sound is then modulated at different rates and using the sine and inverted saw waveforms.
Supersaw trance lead somewhat similar the the Rank 1 - Airwave theme lead. Single saw is fed into the unison module, set to 10. Later in the video a squarewave lfo is modulates the cutoff and a the step module for that common trance gating effect.