Metallica’s bassist Robert Trujillo spoke in an interview by Bass Guitar Magazine and described his thoughts on being funk-based bassist. Seeing himself as a funk bass guitarist, Rob made quite surprising statements. He said:

“In this band, the bass is more like hitting the heavy punchbag. I like to keep it heavy, and even when I was doing all the slap stuff with Suicidal or Infectious, that’s when the low B string became a really strong presence for me.

I’d go for a more tribal effect with my slap. I was trying to get away from the higher pops of the D string, I wanted to go low and deep. I was thinking about the jungle and stuff – just punching that string to get a rhythm.

He also interpreted the relationship of other metal bands and band members to funk. He said:

Raining Blood is the funkiest metal song ever, and the heaviest, too! I’ve always felt Hetfield is the funkiest rhythm guitarist that I know – he can groove, there’s an incredible pocket with him.

So variety is good. It doesn’t mean you always have to play a funky bassline or whatever: it just helps to pull from other styles.

You can read to entire interview from here.