Panting at the Opera (1988)

The D'Arcy sisters own the D'Arcy theater which has been plagued for years by the presence of a Phantom who can drive people into uncontrollable lust by playing a simple melody on his "Satanic pipe." One sister hires a psychic to help find the phantom while her more rational sister hires a structural engineer. In their search, they all fall prey to the Phantom's pipe, but even the Phantom can't hide his identity when the two sisters decide to work together to reveal his true identity.