It has been seven years since violinist Gil Shaham and pianist Orli Shaham released their acclaimed CD "Dvořák for Two." Now their "sibling harmony" returns in a new album by this brother/sister duo, in music by Prokofiev. MPR's John Birge caught up with the siblings just before they set off on a seven-city tour which includes stops at Philadelphia's Kimmel Center, Washington's Kennedy Center, and New York's Carnegie Hall.