| The live tone is incredibly straightforward, you can see how he got it: downtuned Thunderbird through a cranked SVT. You've got the SVT, and it seems like downtuning the ESP or Spector should get you pretty close. I honestly don't think there was anything else going on there, aside from probably some EQ and compression in the PA mix.
The studio sound is harder to tell, partly because half the time he's being doubled by the low-tuned guitar, so a big part of that crunchy low tone is the fact that there are two instruments playing the part. In the non-doubled moments, the bass sounded a little distorted, but not especially special. | 
