Nice chunky analogue square bass from a korg mono poly, with a slow descending resonant cut-off. it has been overdriven.
Bit more raspy. For utter filth I suggest you run this from your sampler, into a reverb with low wet/dry ...
Driven reece bass, recorded in C, cycled (with loop points)
Another Square, this time with a little inverted filter envelope.
Another Korg Mono Poly sample. The distortion introduces some high frequencies, as does the resonance,