Phil Spector is a music industry figure influential behind the "girl groups" of the early 1960s and work with The Beatles. He is credited with inventing the so-called "Wall of Sound".
The concept behind the Wall of Sound was that the sound of an instrument could be enhanced through the recording of several instruments (and possibly additional sounds) at the same time. This became integrated into the concept of modern multitrack recording - unlike a live performance, the instruments on most studio albums are played separately into mixable and modifiable "tracks".
Spector would become violent when drunk, and often threatened people with guns. After a six-year legal battle regarding the death of actress Lana Clarkson, Phil Spector was found guilty of second degree murder in 2009.