Evanescence vocalist Amy Lee has revealed that the band's upcoming new album is "the heaviest record we've ever done".Speaking to MTV, the vocalist opened up about the follow-up to 2006's The Open Door, which is due for release in October."We're having a great time making it," said Amy. "It's totally fun. We're just going for it."Chatting about the band's first new single - which is as yet un-named - Amy explained: "It's really different for us. It doesn't sound like any Evanescence track you've heard before. It's heavy, but the melodies and stuff, I feel like I just did what I wanted."I just literally sang what I wanted to sing, because it was fun and it kind of made me smile, and that ended up being the really fun, cool, catchy thing that got everybody hooked on it," she says. "It also just smacks you right in the face and it's heavy and it's great!"