Sorum and engineer pal Jim Mitchell hired out the studio for a recording session with a band the drummer liked and they were spooked by a spectre who prompted them to flee.
Appearing on U.S. show Celebrity Ghost Stories, the former Guns N' Roses star admits the encounter with the angry spirit is one that has made him a believer.
He recalls, "We recorded all the instruments and the vocals and guitars and what not, and at this point of the evening it was pretty late - about two o'clock in the morning. We started recording more lead vocals and as we were recording everything sounded fine... and then every time we played back the tape there was there was this low kind of a voice-rumbling sound.
"It was almost like a Gregorian kinda chant sound. We were like, 'What is that?' We eventually gave up and the band took off."
Sorum and Mitchell were left alone in the control room listening back to what had been recorded when the engineer was pushed out of his chair by a mysterious force, which followed him to the restroom.
Sorum adds, "He (Mitchell) had this white, state-of-shock look on his face and he said, 'I just saw a ghost... This guy walked behind me in the bathroom and then he disappeared. There was nobody there...' He was starting to get pretty freaked out.
"We walked down the hallway to the lounge and we got right to the door... and a voice said, 'Don't come in here, you're not invited...' There was a presence there.
"Out of the left corner of my eye I saw this mast of air that looked like a small cloud floating across the room... I put my hand out and when I touched it, I backed off... It ran up my arm and down my body until the feeling came to me like ice.
"We were pretty freaked out so we made a quick descent... to the control room. We packed up and I thought, 'I don't think we'll be coming back here because the studio is definitely haunted.'"
Sorum later discovered he wasn't the first star to encounter the studio ghost of the headless dead man who was found in a garbage bag behind the building in 1991.
He says, "They had had clients leave the premises because of strange events and all the employees quit... Studio 56 finally went out of business."