Tapping out a lively beat, the Tuvan drummer set the pace. A classical string quartet joined in. Igils, traditional Tuvan instruments, rounded out the string section. As the Tuvan musicians began to sing, each producing multiple tones, a rich, full sound enveloped the room. A much bigger sound than one would expect from only seven musicians, it was the pièce de résistance of “Unexpected Voices,” a concert featuring the Tuvan ensemble Alash and a classical string quartet at The Chamber Music Society of Lincoln Center (CMS) on January 11, 2008.