With this album, El Gran Silencio seems determined to push at all the limits of Latin alternative music -- or, rather, Mexican alternative, since their ground is very much in the Mexican regional traditions, all laced with a heavy dose of Cumbia, the Colombian rhythm that's become pan-Latin. There's plenty of ragamuffin-style hip-hop in the equation, not only on the title track and "Cumbia Muffin," but also on the scalding "Sound System Municipal." But that's far from being the only string to their bow; they're equally adept at norteño, ska (in fact, "Songbomb" is a great, natural mix of Cumbia and ska), and even a touch of mariachi on "Sueño." Not that they ignore rock. There's Mexican rock & roll here, and even a little hardcore on "Ya." This is an ambitious disc, really moving outward.