Sound Theories Vol. I & II is a 2007 album by American guitarist Steve Vai. The album was recorded with the Metropole Orchestra in Netherlands in mid-2004/2005 and released on June 26, 2007.
Volume I features Vai playing guitar with the orchestra, which has itself earned worldwide acclaim by backing artists ranging from Mike Keneally, Terry Bozzio, Tony Bennett and Natalie Cole to Nancy Wilson and the Yellowjackets. Volume II features the Orchestra performing compositions written by Vai, including "Shadows and Sparks" and "Bledsoe Bluvd."