If the indie-rock revolution has indeed overtaken jam-nation, as some have suggested, then it’s a mixed blessing. On the one hand, many of the unofficial rules that have kept the jam-scene on its toes for the past decade—-extended shows, shuffled setlists and an emphasis on improvisation—-have given way to a new set of concert regulations. In fact, the pendulum has actually swung in the opposite direction, with musicians once again shifting their focus back on songwriting, often favoring tight, polished sets over long, breezy jams. But, on the flipside, indie-rock’s jamband infiltration (or vice versa) has clued a new legion of fans onto some of country’s best underground sounds, proving that both scenes can appeal to the same audience without playing anything close to the same style of music.

While marketing and tour routing certainly play a role in a band’s ability to cross-over in either direction, there are certain key factors which have made certain underground indie-rock bands more digestible to ears weaned on jamband riffs. Given that the jamband movement always seems to flourish in reaction to more straightforward rock and pop (the bubblegum of the early-1960s, the commercialized alt-rock of the 1990s, yada yada yada), it’s odd that indie and jam have forged such a peaceful alliance since the second Bonnaroo Music Festival in 2003. But, upon closer inspection, it actually makes perfect sense: both styles offer underground, credible rock with a strong emphasis on live shows by employing one of three age-old tricks—-humor, energy or dynamic performance.

On this rainy Thursday evening, the Bowery Ballroom, one of New York’s last remaining downtown music Meccas, offered a package of two indie-darlings, We Are Scientists and the Ambulance LTD. Both acts are about as far removed from the conventional jamband tag as can possibly be construed and would surely cringe at the mere thought of being labeled hippie-rock. But, at the same time, both would fit snugly on the same marquees that have made the Secret Machines, Modest Mouse and the Arcade Fire must-see bands for almost any jam-fan. Namely, they both offer great live shows. Playing to a sold-out audience at the Bowery, the final club frontier before an up-and-coming band crosses the 14th street threshold into more elegant uptown venues, it’s quite possible that this pairing of New York indie-darlings might find its ways on a much bigger stage sometime in 2006——and quite feasible that both bands would also be playing Vegoose or Bonnaroo sometime in the near future.

Hailing from New York, We are Scientists are a three-piece, indie-pop outfit, whose sound borders on both Bloc Party’s lush, modern pop and the more aggressive, post-modern alt-rock leanings of Interpol. Though the trio has released both an excellent full-length album, With Love and Squalor, and a series of EPs, it’s through club barnstorming that We Are Scientists has made its name. It’s through its live interaction that We Are Scientists has also tightened its stage banter, a humorous mix of garage-rock hygienic and geeky intellectualism. In fact, after breaking a string, bassist Chris Cain uttered what could be considered the evening’s unofficial motto: “We offer what we can with these impoverished strings.” Offering a quick, 40-minute selection of tracks from both their previous recordings and forthcoming efforts, We Are Scientists developed an immediate rapport with their audience. While known to attracted a somewhat emotionally still hipster crowd, on this night, the audience couldn’t help but sing along to its recent single “The Great Escape,” as well as the standout tracks “Nobody Move, Nobody Gets Hurt” and the popular EP besides “History Repeats” and “Mucho Mas.”

At times the group’s sound, veered towards punkier indie-rock, though the interaction between Cain, guitarist Keith Murray and drummer Michael Tapper remains airtight and immediate. While the group never ventures far beyond its chosen song structure, it takes equal chances through its live interpretations mostly through Cain’s almost lead bass lines and Murray’s fuzzy guitar. Clothed in what can only be described as geek sheik uniforms—- including an obnoxiously white turtleneck—- We Are Scientist’s stage presence also echoed the freaky disconnect of early computer-age, which fell somewhere between New Wave glitz and alt-rock flannel. While the group’s humor shines through the title of its quirky “It’s a Hit,” at the same time, the group is capable of achieving Billboard success—-and deserves it.

On the contrary, Ambulance LTD remains somewhat removed from its audience and even more reserved in its performance approach. A throwback to 1980s’ style shoegazing, a style named after the direction its musicians most often stare, Ambulance LTD are emotionally guarded performers. But what the group lacks in its warmth, it makes up for through its melodic, lush pop nuggets, particularly on LP tracks “Anecdote” and “Heavy Lifting.” At times, the layered interaction of guitarists Marcus Congleton and Benji Lysaght, as well as keyboardist Andrew Haskell, created a surreal, euphoric wall of sound, especially during the intro to the hazy “Yoga Means Union,” which also opens the group’s only proper album, LP. Peaking with the lush harmonies of “Primitive,” and the amplified minimalism of “Stay Where You Are,” Ambulance LTD managed to create sound that was at times pensive, at times relaxed, but always adventurous. In fact, it’s a shame Lysaght spoke to his audience at all at the end of Ambulance LTD’s set. By letting down his emotionally-distant, reverb-drenched voice, the group’s frontman returned his band to earth for the first time during its performance. At the evening’s close, which keeping with indie-rock’s rules arrived after both band’s combined play clocked in at less than two hours, Ambulance LTD thanked We Are Scientists and walked offstage. Unlike its jamband counterparts, the line between fan and performer remained defined, perhaps only to be blurred through the internet —-the biggest quality which differentiates these increasingly incestuous scenes.

It’s refreshing to know that New York rock bands are still creating adventurous music. It’s also refreshing that bands once exclusively associated with the jamband scene, from Lake Trout to Brothers Past, are simultaneously making similar waves in indie-rock circles and festivals. Perhaps one day promoters will even market Coachella and Bonnaroo as a packaged deal—-either that or at least link to each other through My Space.