FORT LAUDERDALE, FLA., OCT. 16 -- The rap group 2 Live Crew won a major victory in its obscenity trial today when the judge barred prosecutors from providing jurors with a written transcript of the performance for which the band was arrested.

The prosecutors now face a battle over the tape itself, which the defense team sought to exclude late today after it was revealed that the state may have violated rules pertaining to the storage of evidence.

In addition, as of today, the trial became an adults-only case. At the request of the defense team, Broward County Judge June L. Johnson banned from the courtroom all spectators under age 18. Johnson said she received telephone calls from parents who wanted their children to view the trial, but the defense team, never missing an opportunity to portray its clients as responsibly handling their material, said they would prefer that only adults be allowed into the courtroom.

The prosecution's case rests largely on the 45-minute tape of the group's adults-only show at a Hollywood, Fla., nightclub in June, although prosecutors also plan to call as witnesses the two undercover detectives who recorded the performance and play four cuts from one of the rappers' more controversial albums.

Most of the tape is unintelligible. The group's performance is all but drowned out by the cheering, screaming crowd. Occasionally, an explicit phrase or expletive can be understood.

To demonstrate the need for a transcript, the prosecutors played the tape to a reluctant Judge Johnson this morning.

Johnson listened to the entire 45 minutes, following along on the transcript, yawning at times, leaning back at others, clearly unimpressed with the lyrics. But she noted that she also read descriptions in the transcript that concerned her.

"I won't call it editorial comment," she said. "But I am concerned that the transcript could detract from the jury's ability to judge the performance as a whole."

The defense badly wanted to keep the transcript out of the jurors' hands. The lyrics seem only more harsh, more explicit when they appear typewritten on a page.

With that round won by the defense, lawyers from both sides moved on to opening arguments, which after all this time were anticlimatic.

Assistant State Attorney Leslie Robson told the jurors that the 2 Live Crew's act did indeed qualify as "prurient." That means, she reminded them, "a morbid and shameful interest in sex."

"You are going to hear graphic depictions of sexual conduct, anal intercourse, women being abused, women being urinated on and caustic comments about homosexuals," Robson told the jury.

She added that the three rappers "incited" the audience, and "simulated sexual conduct" with women from the crowd who jumped onto the stage.

But Bruce Rogow, the lead defense lawyer, advised the jury its job was to judge the entire performance, and that included "the lights, the dancing, the music, the audience participation."

"Nobody is going to deny dirty words," he said.

"Of course there were references to oral and anal sex. Nobody disputes that. Just because those words were mentioned doesn't mean they appeal to the prurient interest."

"Sex is not verboten in this country," Rogow said. "Sex is not something that cannot be spoken of in this country."

He described the music as humorous, exaggerated, a parody. He promised to bring in a witness who would be a "cultural translator."

"Sometimes it's a joke. It may not be your joke," he said.

Following the opening, the lawyers sparred for the remainder of the afternoon over the custody of the micro-cassette used to record the performance. Rogow closely questioned the deputy who was to have placed the tape in the sheriff's department's property room, but learned that traditional chain of custody used to protect evidence had been breached several times.