Spector's signature style was called the Wall of Sound. He used large amounts of echo, doubling and multiplying of musical instruments and the parts to be played, and of recorded parts. The built-up effect gave his records an operatic, theatrical quality. The music sounded "bigger than life". The effect carried over especially well on AM radio, which was how most music was broadcast in the 1950s and 1960s. Spector said the Wall of Sound made "...little symphonies for the kids...".