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. Released on June 26, 2007, Sound Theories is a double-live CD capturing legendary guitarist Steve Vai's electrifying collaboration with the Netherlands Metropole Orchestra.

Volume I features Vai playing guitar with the Orchestra, which has earned worldwide acclaim by backing artists ranging from Mike Keneally, Terry Bozzio, Tony Bennett and Natalie Cole to Nancy Wilson and the Yellowjackets. Together they bring new life to both existing and never-before-heard Steve Vai songs, including "For the Love of God", "Liberty", "The Murder" and "The Attitude Song", among others.

Volume II features the Orchestra performing compositions penned by Vai, including “Shadows and Sparks” and “Bledsoe Bluvd.”

Says Vai, "I wanted to be a composer ever since I was a young boy. Though the guitar fell into my lap and my fingers were glued to the instrument, I studied composition and musical notation long before I even started playing the guitar. Through high school, college and beyond, I kept up my studies but the prospect of getting your music performed by an orchestra when you're only considered to be an over-the-top electric rock guitar shredder seemed virtually impossible. To be able to hear your music performed is the greatest gift a composer could hope for. This was a dream project for me."