Take four lauded Iranian virtuosos versed in both the music of their homeland and the Western classical tradition, put them together with a license to improvise and this result is this stunning double live album (with the production so clear, the applause intruding at the end of each CD comes as a shock). The instrumental waves come from Hossein Alizadeh's tar (a kind of lute) and Kayham Kalhor's kamancheh (spike fiddle), roiling and complementing each other with exuberant brilliance at times, then offering subtle, aching support of vocalist Mohammed Reza Shajarian on others (his son, Homayoun, plays percussion). Often it's impossible not to hear Shajarian as the star, his voice operatically rich and dramatic in its ululations, masterfully building and releasing the tension, but a closer listen reveals that these are works of combined genius, where each musician pushes the others to remarkable heights of brilliance. Forget the impeccable credentials each member brings to the band, the true proof is in the performances — and those really warrant the term awe-inspiring.