The Puerto Rican plena isn't nearly as well known as salsa or merengue. Comb the stacks of any major record store and you'll see that salsa dominates the mainstream Latin music market--not that there's anything wrong with that. Though plena's a little less familiar to Anglo ears, it's just as danceable--and it's a little closer to the street than all those highly produced studio-bound efforts that top the charts. This CD from Plena Libre is the group's 10th release in as many years, so rest assured they know what they're doing. Tight and with an intuitive grasp of each other's skills, the band members have once again crafted a supremely energetic and fun album. They'll be in the Philly area this summer--at the Kimmel Center and Bethlehem's Musikfest. To prepare yourself, slip this vibrant CD into your Discman and hit the Golden Block for walking and listening pleasure. (L.S.)