With its fuzzy sound and gurgling vocals, most of Check Your Head by the Beastie Boys those bratty white rappers who helped take hip-hop to the suburbs way back in the mid-'80s sounds as if it were recorded underwater. Actually, that's the least of the record's problems. A muddled, clanking mess, the 20-track album offers the usual barrage of dumb Beastie boasts (''I got more spice than the Frugal Gourmet!''), all set to sophomoric attempts at rap, lounge-lizard organ riffing, and skinhead punk. (The new angle is that they play all their own instruments for the first time, but the flaccid metal riffs on ''Gratitude'' only make you nostalgic for sampling.) The Beasties' first album, Licensed to Ill, was an obnoxious, and funny, pop-culture carnival; six years and many imitators later, it still stands as the definitive white rap album. At this rate, it will have to stand as the Beasties' shining hour, too.