Ahhh....A good metal bass sound. There are several ways, and chorusing is only a small part of it. I'll reference the FF sound here 'cause I am more familiar with them than Napalm Death.
First, you need to know how the bass you are trying to emulate is tuned. FF tunes WAY low. Low "A" I think. That totally changes all potential settings you may use for standard tunings. You will have WAY more low end and mid range just from your tuning, so keep that in mind. You will also have a less "precise" sound that you will need to compensate for in your actual playing tecnique....
Second, the bass itself has a great tone and the signal is HEAVILY processed. WAY more than just overdrive is going on there. You've got a shit load of compression, very elaborate eq, some very well done stereo tracking, chorus, reverb, delay, AND top shelf gear that would cost you and I a shit load of $$.
The biggest thing they have going on that you can work with is the bass signal (to my ears) is split, and only the upper frequencies are distorted. The lower frequencies seem to not have any sort of overdrive at all. If you focus your efforts on that aspect of it, you will come close. Use those upper frequncies for all the effects and just tighen up the low end. The bass carries ALL the low end for FF - the drums are more for impact and presence than low end. Experimenting is key for that sound. FF really likes technology and processing, so unless you have the latest and greatest gear, all you will get is close to that sound.....
MrStitch - The Pantera bass sound, IMO, is very straight forward and simple. I'm not sure how closely you can emulate it with Hartke gear, though. Rex used Ampeg gear on that album (on all of them maybe?) and Ampeg bass gear has it's own color and "looseness" that I have not been able to find anywhere else.
I will admit that I have not spent much time trying to copy the Pantera bass sound, but it sounds to me like it is just the slightly overdriven tube sound that Ampeg has along with clean playing and a solid recording technique.
Another example of a GREAT bass sound is Carcass' Swan Song album. They also used Ampeg gear for bass. The tone they got was just crushing. No fancy tricks either.
