Three other Justices (Reed, Vinson, Burton), who construed the ordinance more narrowly, stated in dictum that an absolute prohibition on the use of sound trucks would be "probably unconstitutional as an unreasonable interference with normal activities." Id. at 82, 69 S. Ct. at 451. Thus, at least six of the Justices considered that an absolute prohibition either was, or probably would be, unconstitutional.
The only apparent legitimate state end to be served by the regulation of sound trucks, and the only justification for such regulation advanced in this case and cases involving like ordinances, Saia v. State of New York, 334 U.S. 558, 68 S. Ct. 1148, 92 L. Ed. 1574 (1948); Kovacs v. Cooper, 336 U.S. 77, 69 S. Ct. 448, 93 L. Ed. 513 (1949), is the protection of the tranquillity of the community or, expressed differently, protection of the community's citizens from disturbance by "aural aggression." A municipality's interest in this regard is very real - especially in our increasingly sound-polluted society - and reasonable regulation of sound trucks, limiting their operation as to time, place of volume, is constitutionally unobjectionable. Kovacs v. Cooper, 336 U.S. 77, 69 S. Ct. 448, 93 L. Ed. 513 (1949). But First Amendment freedoms are so important to our democratic society
that they will be staunchly protected by the courts from unnecessary restriction. "These freedoms are delicate * * * supremely precious" and, in order to protect them, "government may regulate in the area only with narrow specificity." N.A.A.C.P. v. Button, 371 U.S. 415, 433, 83 S. Ct. 328, 338, 9 L. Ed. 2d 405 (1963).
Sound trucks do not in all cases constitute a substantial invasion of societal peace. For one thing, a sound truck may have its volume turned down to a relatively low level, for example in a case where other means (signs, displays, etc.) are employed to attract people, and the audio device is used to deliver a message to those who have gathered nearby. For another, even though it be admitted that, as a practical matter, sound trucks generally have to achieve a pitch that rises above other street noises, see Kovacs v. Cooper, 336 U.S. 77, 81, 69 S. Ct. 448, 93 L. Ed. 513 (1949), this is not tantamount to a finding that the pitch is socially disruptive. What the citizenry is accustomed to is not a constant level of sound, but to an average noise level which includes both periods of relative quiet and periods of relatively harsh and strident noises. Only if a sound truck is a major contributor to the harsh sounds, or if it produces sounds of unusual harshness, or if its harsh sounds last for an unusually long duration, will its sound substantially invade a community's tranquillity. We are of the opinion that sound trucks frequently do not cause substantial disruption in the context of our society. In light of the paramount importance of free speech and of possible uses
of sound trucks that are relatively innocuous, it seems to us that certain uses of sound trucks cannot be justifiably prohibited by the municipality, and thus Darby's absolute prohibition on the use of sound trucks is unconstitutionally overbroad.
The subject plaintiff was speaking to at the time of her arrest is one of public interest. It is an issue in the political campaign which will reach its culmination on November 4. Unless plaintiff has preliminary relief before that date, one phase of her attack will become moot. Hence, unless relief is granted, plaintiff will suffer irreparable injury. And, in light of the foregoing discussion, it seems likely, if not inevitable, that plaintiff will prevail on final hearing. The criteria for granting a preliminary injunction have been met.