The beat in “The Beat Goes On” owes less to Sonny and Cher than an anonymous bass guitarist named Carol Kaye, who says in this fascinating documentary that she was “making more money than the president.”

Kaye was a small group of crack musicians who were brought in to provide supercatchy riffs for the likes of Nancy Sinatra (“These Boots Are Made for Walking”), Herb Alpert and the Tijuana Brass (“A Taste of Honey”) and the Mamas and the Papas (“California Dreamin’ ”). Dubbed the Wrecking Crew, these musicians also worked with Simon and Garfunkle, and Brian Wilson says even he brought them in, because they could play better than the actual Beach Boys.

Largely jazz musicians, these unsung geniuses were employed on thousands of recordings in the 1960s into the early 1970s, when producers like Phil Spector wanted to knock out high-quality albums in days instead of the weeks it would have taken using less skilled touring musicians.

The documentary was filmed in the 1990s by Denny Tedesco, whose father Tommy is credited as the most recorded guitarist in history, including the instantly identifiable themes to “Bonanza” and “Mission: Impossible.” A Kickstarter campaign was required to finally raise the money to pay for music rights for the amazing soundtrack.