The Naumber Acoustic Bandshell is in the south-east portion of Central Park. Nearby is a grassy open area called Sheep Meadow that was designated by the City as a quiet area for passive recreation. Just beyond the park and within range of the bandshell are apartments and residences of Central Park West. The City tried to regulate the volume of amplified music at the bandshell. The ordinance requires performers to use sound amplification equipment from the city and to use its hired sound technician. This dispute erupted over music and the right to regulate it under this ordinance. The city received numerous complaints about excessive sound amplification at respondent's concerts from park users and residents of areas adjacent to the park. When respondent sought permission to hold its upcoming concert at the bandshell, the city declined to grant an event permit, citing its problems with noise and crowd control at RAR's previous concerts. The city suggested other alternative sites for the concert. RAR declined and filed suit seeking an injunction directing issuance of an event permit. After respondent agreed to abide by all applicable regulations, the parties reached agreement, and a permit was issued. After learning that it would be expected to comply with the guidelines at its upcoming annual concert in May 1986, respondent returned to the District Court and filed a motion for an injunction against the enforcement of certain aspects of the guidelines. The District Court preliminarily enjoined enforcement of the sound amplification rule. RAR was permitted to use its own sound equipment and technician. RAR's 1986 concert generated complaints about excessive noise from park users and nearby residents. After the concert, respondent amended its complaint to seek damages and a declaratory judgment striking down the guidelines as facially invalid. The District Court upheld the sound amplification guideline. The Court of Appeals reversed; the city's guideline was valid only to the extent necessary to achieve the city's legitimate interest in controlling excessive volume but found there were various alternative means of controlling volume without also intruding on respondent's ability to control the sound mix. The Court of Appeals concluded that the sound amplification guideline was invalid because the city had failed to prove that its regulation 'was the least intrusive means of regulating the volume.'