Terrence Paul Melcher was an American record producer who was instrumental in shaping the mid-to-late 1960s California Sound and folk rock movements. His best-known contributions were producing the Byrds' first two albums Mr. Tambourine Man (1965) and Turn! Turn! Turn! (1965), as well as most of the hit recordings of Paul Revere & the Raiders and Gentle Soul. He is also known for his collaborations with Bruce Johnston and for his association with the Manson Family.

The California sound is a popular music aesthetic that originates with American pop and rock recording artists from Southern California in the early 1960s. At first, it was conflated with the California myth, an idyllic setting inspired by the state's beach culture that commonly appeared in the lyrics of commercial pop songs. Later, the sound was expanded outside its initial geography and subject matter and was developed to be more sophisticated, often featuring studio experimentation.