After 90 rousing minutes of power chords, Pearl Jam has surrendered Madison Square Garden's stage to a perplexing spectacle. Dour men in dark suits are methodically stacking cardboard file boxes in neat rows behind lead singer Eddie Vedder's microphone.

Some fans at the concert late last week are baffled, others are whooping giddily. To anyone who's been following the Lewinsky scandal, the boxes look familiar. Has the Starr report just been carted onstage?

"Ken Starr's people wanted a few backstage passes and I told them I'd do it if I got a copy of the report," Vedder wryly informs the audience. The boxes, it turns out, are merely props, but they give Vedder the chance to lacerate the independent counsel for distracting the country from topics that actually matter.

"I'm sorry, the stage is not the place for my personal problems," Vedder deadpans with a grin once he calms down, tossing the empty boxes into the crowd.

This is the new, mellower Pearl Jam.

Music critics have lately suggested that rock's perpetually aggrieved quintet, which plays Merriweather Post Pavilion tonight and a Voters for Choice benefit tomorrow at Constitution Hall, has declared a truce. The members of Pearl Jam, they say, have made peace both with each other and, more remarkably, with the commercial demands of corporate rock, an industry that for years they have either uneasily resisted or battled.

And it's true the band isn't warring the way it once did. Pearl Jam has abandoned its very public boycott of Ticketmaster, which it has long crusaded against, alleging that the company is a monopoly that gouges fans. Recently the band cut a video for MTV, a nod toward self-promotion that it once considered a tad craven. Tellingly, the band's critically touted fifth album is titled "Yield," a hint that rock's most high-minded ensemble could be ready to shake hands with fame.

But the Pearl Jam retreat is tactical rather than total. As Vedder's rant indicates, the band will continue to gleefully irritate anyone who believes that chart-topping rock musicians should just shut up and play. The Voters for Choice show is an abortion rights benefit, and you can bet that Vedder will share a few words on the topic.

"There are definitely days when I feel like you can't change anything and why even imagine that you can and why would you want to," Vedder says minutes before taking the stage. "Is there some kind of strange ego thing? I don't feel that way. I feel like it's somebody's responsibility to speak up about this stuff."

As for capitulations to commerce, there have been some, but not many. No corporate sponsors are underwriting the tour, and the band isn't selling songs for minivan commercials. To keep prices low -- a Merriweather ticket costs about $33, service charges included -- the show is bereft of pyrotechnics, the only extravagance a set of oversize candles in towering Pottery Barn-type holders. In cities where they can dodge Ticketmaster, they're dodging -- Merriweather uses a Ticketmaster rival, Protix, for its seating.

"We don't have Pearl Jam credit cards," says bass guitarist Jeff Ament. "We could make more money if we stayed out on tour for six months, we could make more money if we charged $40 or $50 for a concert ticket."

"In the long run it's still our business sense not to do all that," says guitarist Stone Gossard. "We're only doing things a bit at a time. We hear, You guys will only make this much money if you go out and tour for a month.' Well, maybe that much money is enough."

It's been seven years since Pearl Jam released "10," an album that helped make flannel lumberjack shirts fashionable and has since sold more than 8 million copies. The record, along with Nirvana's "Nevermind," launched grunge, a thundering combination of brawny guitars and alienation that seemed to strip the varnish off rock and transform it into something raw and unabashedly emotional. The music added a sonic roar to punk's energy and angst.

Time magazine put Vedder, now 31, on its cover in 1993 and anointed him a future Rock-and-Roll Hall of Famer, if Cleveland got ever around to building the place. But acclaim only fueled the band's refusal to punch such standard tickets of pop stardom as interviews and videos. And in 1994, the band began its campaign against Ticketmaster, opting to play far-flung or smaller venues where the company didn't get a cut. Two members of the band went to Capitol Hill to decry the company as a monopoly before a House subcommittee.

The battle proved unwinnable, and it nearly broke up the band. A 1994 tour was canceled and the one the following year was truncated, in part because the group couldn't cobble together enough reasonably sized non-Ticketmaster venues. The strain stirred perennial tensions within Pearl Jam and fans groused that catching a glimpse of their heroes was becoming impossible. Soon after a bout of food poisoning forced Vedder off the stage in San Francisco in 1995, there was talk about packing it in.

"In the end, we got to see what it was like up close to be crushed by a huge corporate giant," says Vedder, taking a long puff on a cigarette. "It was pretty exciting, and educational and disheartening."

By wandering a few paces off the high road, Pearl Jam these days seems more relaxed than ever. The show here Thursday reflected a rediscovered exuberance, with the band dusting off classics like "Alive," "Dissident" and "Jeremy" and digging deeply into "Yield," all of the music delivered with an upbeat urgency that was missing in previous tours. For good measure, Vedder destroyed a couple of mike stands, Pete Townshend style.

Backstage before the show, the band members were still talking like CEOs of a business that doesn't particularly like business. Vedder has arrived in the middle of the interview in a pair of black jeans and a green Army jacket, tiptoeing toward a tape recorder as if it might mug him. Shy and preternaturally intense, he's got a quick answer when asked why he's enjoying the road these days.

"This is the only interview we've done, so it's been fun," he says.

Nobody seems particularly bothered that "Yield" has sold 1.3 million records, a modest number compared with super-sellers like "Vitalogy," the 1994 album that tallied nearly five times as much. If the band isn't a full-fledged media phenomenon again soon, nobody in the room would mind. Maybe in the future, they say, they'll play with little fanfare to a core audience and the music press will barely take note.

"This is a different phase in our career," Gossard says. "Look at Jimmy Buffett. He goes out every summer and has a huge impact on his fans, but nobody is reading about the new Jimmy Buffet record in Rolling Stone or the gossip columns."

"A lot of bands have a life of just a couple or three records or something," says Vedder, hand-drumming on his leg as opening act Ben Harper starts his set. "Year 2000 will only be our 10-year anniversary, so it's not like we've been around that long. I feel like we're kind of halfway there to how good it can get."

Gloria Steinem, who will emcee the Voters for Choice benefit, has spent time with the band members and thinks they've learned better than most groups to control the inevitable cynicism that often follows an onslaught of adulation. Certainly, she notes, Vedder & Co. are faring better than the Beatles, whom she followed around for a day and a half of an early tour as a young reporter for Cosmopolitan.

"The Beatles were sort of taken up by, and hostile to, the world," she says. "They were a little contemptuous of their fans. . . . I'm not trying to be critical of them, because who knows what they were going through. But fame seemed to be controlling the Beatles, while Pearl Jam seems to be controlling fame. They're trying to hang on to their private lives and say something to the fans that has true meaning about things that matter."

No doubt some observers will forever want to grab Pearl Jam by their frayed T-shirts and whisper, Dudes, you're a rock band. Lighten up. But Vedder is most comfortable talking about weightier topics, like the need for abortion rights and the rising power of entertainment conglomerates. He could be the only rock superstar who is genuinely passionate about antitrust. To this day, he's smarting over his dealings with the Justice Department, which had invited the band to testify before Congress about its dealings with Ticketmaster.

"Then one Labor Day weekend, we get a two-line memo from them saying they've dropped the Ticketmaster investigation," Vedder says. "That was tough."

Pearl Jam was formed with some help from the U.S. Postal Service. Gossard, Ament and guitarist Mike McCready were playing in Seattle during the summer of 1990, casting about for a lead singer and recording vocal-less demos built around Gossard's thick guitar riffs. The trio learned about Vedder, who then lived in San Diego, through future Pearl Jam drummer Jack Irons, and sent him a cassette. Vedder promptly penned some lyrics and mailed the tape back. With everyone ecstatic about the results, Vedder boarded a plane to Washington state.

The band played its first gigs under the name Mookie Blaylock, a homage to the NBA point guard. After complaints from Blaylock, they dropped the name and rechristened themselves Pearl Jam.

In 1991, they took a month to record "10," after Blaylock's jersey number. Eventually the album peaked at No. 2 on the Billboard charts. In an age of family dysfunction, Vedder proved the ideal troubadour. Possessed of a thundering baritone that radiated both wounds and defiance, he sang about emotionally battered children and their broken lives rather than chicks and cool cars.

A high school dropout, Vedder was a gas station attendant in 1990; three years later fans mobbed him when he went out at night, and one drove a car into his house. In recluse mode, he hired a couple of guards to watch over his Seattle home, according to Rolling Stone. Even the Domino's Pizza boy got a frisking. Every member of the band seemed flabbergasted by their sudden success.

"When it first happened, nobody had any idea it would explode to that level," McCready says.

Through two well-regarded follow-up albums -- "Vs." and "Vitalogy" -- Pearl Jam spawned countless imitators. But 1996's cheerless "No Code" was a critical and popular disappointment. Because the band lacked a radio-friendly hit and was avoiding the country's biggest venues to sidestep Ticketmaster, its profile was low.

"Yield" is the band's least brooding, least pious effort in years, and it's Pearl Jam's most collaborative to date. The album marks the first time that everyone in the band, not just Vedder, showed up at the studio with fully realized songs in hand. Decentralizing the writing duties took the pressure off him and has given the lie to any notion that Pearl Jam is simply a group of solid musicians fronted by a guy with spectacular pipes.

"Other people might not be as noticeably talented, but given a chance to grow, we've got a lot to offer," Gossard says.

Onstage, the new team approach to musicmaking produced a show that the band seemed to enjoy as much as the fans. Until recently, Madison Square Garden was off limits because it sells through Ticketmaster. Mindful that he'd fought the hall and the hall won, Vedder kicked off the evening waving a white flag. Sort of.

"I'm sure you don't give a {expletive} how you got your ticket and I know I don't give a {expletive} how you got your tickets," Vedder announces to cheers. "Before I came out here, a friend said, You might have sold 30 million records, but you ain't {expletive} until you play Madison Square Garden.' "

The peace notwithstanding, Vedder warns that nobody should expect to see him and his colleagues leaping on the corporate-rock treadmill anytime soon. He'll still gulping notoriety and fortune at his own pace, and it could be a while before he's on the road again. "Someone suggested that because we're having so much fun, having such a good time and things are going so smoothly, maybe this means the band will do this every year," Vedder says. "No, definitely not." Staff researcher Richard Drezen contributed to this report. CAPTION: "I feel like we're kind of halfway there to how good it can get," Pearl Jam vocalist Eddie Vedder says. CAPTION: The band is no longer fighting with Ticketmaster but will still annoy anyone who thinks that rockers should keep their opinions to themselves. CAPTION: Pearl Jam plays at Merriweather Post Pavilion tonight and at a Voters for Choice benefit at Constitution Hall tomorrow.