Canadian producer Bob Rock, who is best known for his long creative partnership with METALLICA, tells The Canadian Press that he he has enjoyed the freedom to explore different projects since parting ways with the group following the release of 2003's "St. Anger"."When I was with them, they were kind of all-encompassing," he says of working with METALLICA. "Their whole trip was so almost draining. And I didn't get a chance to do a lot of other things while I was working with them, so I'm really having a lot of fun." Rock, who produced METALLICA's smash self-titled '91 album and remains on good terms with the iconic metal group, has only positive things to say when asked whether he'd listened to METALLICA's critically panned collaboration with Lou Reed, "Lulu", which currently has a 41 score on the review aggregator Metacritic.com. "I'm a huge Lou Reed fan and a huge METALLICA fan ... I know those guys very well, and it sounds like they did what they wanted to do, and I see the art in it," Rock said. "For METALLICA, I think it's amazingly courageous for them to do a record like this, and to put it out like they did, 'cause they didn't really put out as a side project, they put it out (as) a METALLICA record with Lou Reed. That's really gutsy." In a 2006 interview with Revolver magazine, METALLICA drummer Lars Ulrich stated about the band's decision to work with producer Rick Rubin on 2008's "Death Magnetic" after spending 15 years and five albums with Bob Rock, "In 1990, when we started using Bob, it was because Bob made all the best rock records that were going on at that time MTLEY CRE, DAVID LEE ROTH, THE CULT and he was involved in the engineering of all the BON JOVI records. Everything that was going on in the late Eighties was all about Bob Rock. And now, everything that's great about rock from SLIPKNOT to SYSTEM OF A DOWN to the CHILI PEPPERS to MARS VOLTA, and even the JOHNNY CASH and NEIL DIAMOND records it's all Rick Rubin. The same thing that brought us to Bob 15 years ago is now kind of bringing us to Rick. We want to work with the guy who's got the total finger on the pulse. And Bob was the first one to bless it, to say, 'Look, I don't know what else I can offer you 15 years later.' We finish each other's sentences. We know what he's going to say, and he knows what we're going to say. We made, what, like, five records with him? And he really had been the fifth member of our band for the last 15 years. As painful as it is, getting his blessing first was really important to us. So, so far, every side of it has been great."