Florida Supreme Court hearings don’t often involve boom boxes and subwoofers. But justices Thursday took up a constitutional challenge to a state law that allows motorists to get cited for blasting their car stereos. Attorney Richard Catalano, who got a ticket in 2007 in St. Petersburg, argued that justices should toss out the law, which says a stereo is too loud if it is “plainly audible” from 25 feet away. At one point during the arguments, Catalano slowly backed away from the podium and asked justices in a conversational tone, “Am I plainly audible now?” Timothy Osterhaus, a state deputy solicitor general, said the law was intended to improve safety, as drivers would be better able to hear sounds of such things as emergency vehicles. But Justice Jorge Labarga questioned that argument, saying the law would allow loud boom boxes on top of cars but not loud stereos inside. Also, Labarga questioned an exception for political speech coming from a vehicle such as a sound truck. “I don’t see how it is safer to hear a politician make a speech than to hear a preacher give a sermon,” Labarga said. “Where do you draw the line?” Catalano said his windows were up when he got ticketed. He acknowledged, however, that he had a subwoofer in his trunk. “You’re lucky that’s all you had in your trunk,” replied Justice Barbara Pariente, drawing laughter in the courtroom.