By Linda KohanovAmidst his rich synthesized sounds, pop textures, and spicy Latin rhythms, Rubaja also performs on such exotic South American instruments as the charango (a guitarlike instrument made from an armadillo shell) and the bandoneon (a button accordion made famous by fellow-Argentinian Astor Piazzola). Guest artists include trumpeter Mark Isham and percussionist Alex Acuna, among others.