Well, this is a mad bass line on the song "The Press Corpse" by Anti-Flag(no, im not fond of there politics

) You can click to listen to it on my myspace
www.myspace.com/ticklemefaggot or
www.purevolume.com/antiflag
Im just wondering, hows this guy doing it, im better at making bass lines like what he is doing in the chorus(kinda like a walk down.) I can hear the guitar, and im guess the guitar is on the root note, and then bass is just playing the Major, Minor 7th arpegio and so on with that stuff( im not all the way educated with that stuff). thanks!
P.S, he play a geddy lee, any clue what type of head he has?