Some Tool fans have been around for the long haul and truly appreciate the sort of aural artiness in which the group traffics. But many others are Maynard-lovers-come-lately -- and their reaction to Isis, a musically simpatico opening act, should reveal the depth of their loyalty. Isis discs such as 2004's Panopticon feature long, involving compositions that juxtapose sonic force and terrible beauty with tremendous skill, as well as lyrics whose imagery often displays a darkly poetic quality. But because Turner and company don't increase the accessibility of their work by piling on the melodies and hooks, songs like "In Fiction" and "Backlit" require effort on the part of listeners -- especially those who are unfamiliar with the tunes. Of course, ticket-buyers who are into Tool for artistic reasons instead of trendy ones are capable of meeting the band halfway, and they'll be rewarded for doing so. As for poseurs, they're apt to bitch and moan until the stars of the show take the stage. For everyone's sake, let's hope the former outnumber the latter.