Right
Try creating your midrange bass totally separate from your subs. Some will say to frequency split your basses, which can work well, but I get the best results using this technique. I usually start out by creating a melody / riff with a nice solid sub bass. Once done, I'll put the sub channel in mono, and roll off all the high end down to around 100hz (you could go lower, but I modulate my sub bass to bring out some small harmonics here and there so 100hz is perfect for me)
Now for the crunchy midrange, a lot of people will tell you a million different oscillator combinations to achieve what you want, but again, after much trial and error, I have found you cannot beat a bog standard, simple, low octave saw wave.....nothing else from the synth at all, no unison, no modulation, no overdrive........NOTHING! All the movement and diversity comes from what you add after the saw wave synth.
Again, there are so many combinations of FX chains you can use to get the desired effects. My usual routine begins with Sugarbytes wow filter with vowel mode enabled, on a band reject filter turned fully to the right. From here I'll add some chorus, with varying dry/wet depending on how wide I want the sound to be. After this I will add an EQ with two sharp notch filters around the midrange area of the frequency spectrum and I'll link those to a pot wheel on my midi controller, reversing one of them so when I twist the wheel, the notches will modulate in opposite directions, giving the desired movement.
Depending on how much movement you require, you can also link up the wow filter, and dry/wet of the chorus all to the same pot wheel for maximum effect.
That's the basics of it really. You can go crazy from here, maybe you will want to export a clip of the channel, with some movement, and bring it back in, and throw on another wow filter or some distortion? adding more movement along the way? choices are endless, the hardest part is knowing when to stop and say that the sound is done!
But I'll reiterate on what I said earlier, my best results have come from playing around with a simple low octave saw wave, nothing else. I've spent years trying to perfect my basscraft, using a multitude of different combinations ands effects. This may work perfectly for you like it did me, or you may use this technique and stumble on something better, it may even be useless to you....who knows, but it cant hurt to try right?