I'll have a go (at least try) the first tune. This is by no means a recipe, but rather some ideas that may lend itself to design the sound itself.
Sounds like two different bass sounds, the main one sounds a bit like a square (for the thick, hollowed sound), that has been overdriven via distortion, filter(s) overdrive or sometype of wave-distortion/shaper. The metallic overtone that sits on top of the bass sounds like a "singing" resonance (i.e. resonance with a high setting) or perhaps some kind of FM. The filter cutoff and resonance seem to modulated via envelope (or slow ascending LFO) with a slightly high attack time, which lends itself to creating that ramping "wah" timbre. The majority of the highs seem to be rolled of, making the bass as very low/low-mid dominant in the spectrum.