Complex sentence: Daytime recording was reserved for ad agency clients, and expensive, high quality European microphones used in the studio were meant only for delicate orchestra recordings, not for loud rock, most of Howard and Ron's experimentation was done at night, and without supervision.
Split into simpler sentences: Daytime recording was reserved for ad agency clients, and expensive, high quality European microphones used in the studio were meant only for delicate orchestra recordings, not for loud rock. Most of Howard and Ron's experimentation was done at night, and without supervision.