I don't find the bass tone THAT growling in Left Hand Path, in fact compared to the HM2 it sounds surprinsingly clear (which IMHO is qui te a part in the overall feel as it stands out of the mix more than if it were more distorted and blended with the guitars!
Anyway, I find it quite similat to the bass tone in Autopsy's Severed Survival,, even if this one is more distorted and a little deeper sounding too, so you could maybe try to find infos on their setup too!
If you find anything about either of these tones, I'd be really interested in it though, as looking for infos mainly ends up as "they had no clue what they were doing"...