Voices of Desire

Voices of Desire is a 1972 horror film directed by Chuck Vincent under the stage name Mark Ubell. The film stars Sandra Peabody, Gus Thomas, and Marlene Willoughby. The plot concerns a young woman named Anna Reed (Peabody) who recounts her claims to a psychiatrist that she was involved with a cult whose members were either murdered or committed suicide after she begins hearing distorted voices.

Synopsis from Wikipedia, CC BY-SA 4.0. Everything below written here.