MANSFIELD - With the yearly Ozzfest making only one stop on a single tour date, the Rockstar Energy Drink Mayhem Festival stepped in to fill the giant hole left in the hearts of heavy metal music fans Tuesday.

The nearly nine-hour long festival at the Comcast Center brought plenty of metal, some of it good and some of it typical.

For those of you uninitiated into the heavy metal music genre, you should know that it is as much a culture as a genre of music. Typically. the darker the music and lyrics, the more fans will like it. However, you should know that the key difference between a good metal band and a bad one is that a good metal band doesn't take itself too seriously.

This brings up the one problem with the main stage, Disturbed. Disturbed can be summed up as a band comprised of meatheads, that just attracts meatheads for fans. One concert goer put it simply, "I can't stand it. It's like I keep hearing the same song."

That's how bad the music is. As for the show they put on, well, it's almost a one man show. This is where the lead singer takes himself too seriously. He starts by having himself wheeled out onto the stage on a coffin shaped piece of plywood in a straightjacket, wearing a Hannibal Lecter mask. Seriously? Seriously.

He also makes his lyrics the focal point of all the songs, so the music suffers because of it, and you just get the same repetitive power cords that really have no value at all.

Put this against the other bands on the main stage, Mastodon, Dragonforce and Slipknot, and you get a third act slump.

The rest of these bands put the music first. Mastodon is a seasoned group that has garnered fans for the last nine years.

Dragonforce sharp, tight

Dragonforce is the pinnacle of not taking itself seriously - obviously, they named themselves Dragonforce. They are a mix of fantasy metal, Iron Maiden and the whole genre of speed metal. Their music is sharp, tight and faster than anything you've heard before. They know what they are doing.

Finally, Slipknot took the whole place by force with their muddy lyrics and full force metal sound. Their performance was great. How else would they have garnered enough fans to fill the Comcast Center?