Music producer Phil Spector appears in court during his murder trial at Los Angeles Superior Court in Los Angeles August 16, 2007. Spector is accused of fatally shooting actress Lana Clarkson in his home in February 2003. — Reuters pic

LOS ANGELES, Jan 18 — Phil Spector, who revolutionised 1960s pop music with his “Wall of Sound” production technique but who was imprisoned in 2009 for murder, has died at age 81, authorities said yesterday.