well I assume you mean the woap woap sound bass noise as opposed to the two or three other bass sounds going on in those tunes.
anyway its all about mapping the lowpass filter of the synth to an envelope, so that when you trigger the note, the filter opens up, allowing the higher frequencies of the synth to pass through, making that 'bwoap' sound.
set the filter cutoff to a low point, so that when you play the synth it has the 'sub bass only' sound you;re looking for at the initial stage of the bwoap.
assign the filter cutoff to an envelope. how to do this will depend on the synth you;re using... (which synth ARE you using?) you should be able to figure it out. it'll be in the routing section if there is one. if there are more simple envelopes with just attack and decay, rather than ones with hold, sustain and release as well, i would recommend using those more simple ones.
when you hit the note, you'll want the filter to open up to a certain extent over a certain amount of time... these amounts are obviously artistic decisions but the time of the attack is what will dictate how long it will take for the filter to open up and obviously dependent on the tempo of the tune. the amount it opens up will depend on the intensity you set when you map filter > envelope. usually reading something like 0 (no intensity) to +1 (max intensity, positive polarity) or -1 (max intensity, neg polarity) all that means is that if its on +1, the filter will OPEN with the attack phase of the envelope and then CLOSE with the decay... whereas -1 will CLOSE with the attack phase and OPEN with the decay.
thing is though is that when the attack phase is over, the decay phase kicks in and your filter will start to close again as long as the note is still being played, so you want to make sure that either the attack phase is long enough so that the note length isn't long enough to reach the end of the attack phase, OR that the decay phase is very long (or set sustain to maximum) so that the filter doesn't start to close again. you'll also want to make sure that the volume envelope for the synth has a very fast release time, which means that when you stop playing the note, the volume drops off rapidly instead of dribbling away.
makes sense? welcome to the world of synth programming.
. The sound i am looking for is a wibbly wobbly (niche) kind of sound, like you hear on many 4x4 or Baseline tracks.
