The so-called lo-fi aesthetic that developed in the 1980s among American indie groups like the Replacements wasn't really an aesthetic at all. Independent record labels' hands-off policy had less to do with respect for artistic expression than it did with lack of liquidity.

In the '90s, however, lo-fi has become a true aesthetic. Groups purposely keep their music messy and their sound quality dodgy in order to emphasize originality rather than virtuosity and gloss. As home recording becomes cheaper and better in quality, the aesthetic loses part of its justification, but some of the most exciting music to emerge in the past five years has been faithful to the lo-fi approach.

Purposely or not, no indie has advanced this cause as far as Chicago's Drag City. Since 1990, the label has released a steady stream of diverse and challenging music -- from the Daliesque hoodoo of Royal Trux to the rockless instrumental experiments of Gastr del Sol to the Appalachian authenticity of Palace Music -- whose only unifying characteristic is its total disregard for what's considered commercial or, for that matter, hip. Even Pavement, probably the most influential indie band of the decade and the pioneer of lo-fi for lo-fi's sake, released its first singles on Drag City.

P-Vine Records, which licenses the label for distribution in Japan, presented three stylistically dissimilar DC artists March 28 at Club Quattro in Shibuya.

The opening group, Plush, is not a group at all, but a frizzy-haired singer-songwriter named Liam Hayes, whose main claim to fame has been playing keyboards on the morose country tunes of Will Oldham's Palace Music. Hayes' music sounds ready-made for lush strings and heavenly background choruses, but all you hear on his demolike debut, "More You Becomes You," is minimalist organ and piano set behind his mournful and immature singing voice.

An obvious student of '60s tunesmiths like Jimmy Webb, Hayes has a knack for melody, or perhaps I should say he has a knack for one melody, since all his songs sound alike. At Quattro, he was backed by members of the headliner, Royal Trux, and the assistance gave his songs more substance and helped mask the fact that he's a crummy singer. Despite his waifish appearance, Hayes is bold (anyone who titles his first single "Soaring and Boring" has guts), and he performed the entire album in order, pausing only once.

Like Plush, Smog is also one person (this tendency to obscure one's ego with the guise of a group seems to be a Drag City trademark), whose name is Jim Callahan, a legendary mainstay on the label since 1991. Unlike Plush's debut, Smog's records feature bass and drums and even the occasional background chorus. Reversing Plush's live gambit, Callahan didn't avail himself of the services of Royal Trux and performed his entire 45-minute set with only guitar and tambourine, which he tapped with his foot.

Whereas Plush's music is as melancholy as an empty house on a rainy Sunday afternoon, Smog's is as depressing as a windowless cell on a summer day. Callahan's only concession to musical nuance is dynamic. He started off each song with an indiscernible strum that slowly gained in volume under his steady baritone, which sounded like it belonged to someone who adored Leo Kottke for his singing.

Though a few people were apparently familiar with his excellent new album, "Knock, Knock," the audience as a whole didn't know what to make of him. The songs were even more low key in concert than they are on the record, but Callahan's lack of stage personality focuses your attention on his lyrics, which are stunningly evocative.

"When I take the prisoners swimming, they have the times of their lives," he sang without feeling. "I love to watch them floating on their backs, unburdened and relaxed."

Consistent with the evening's policy of no-expectations-are-good-expec- tations, Royal Trux was minus its guitarist and guiding force, Neil Hagerty, who, according to the promoter, hates airplanes. That left it up to Jennifer Herrema, the group's blonde lead singer, to wield whatever star power the band possesses.

Herrema wisely limited her 50-minute set to real songs rather than the angular noise that characterizes a lot of RT's recorded output. Dressed in biker chick couture (dungaree jacket and bell bottoms, wrap-around shades, loose white T-shirt and with a lot of hair in her face), she is at least visually arresting (she also models for Calvin Klein). Her voice is famously lo-fi -- Janis Joplin's lower range reduced to a fervent puking sound -- but she can sneer and shout and knows how to lean on the mike stand like Iggy Pop. Since RT's music retrofits its discordant postmodern sound with what is basically brainless white-boy boogie and blues rock from the '60s, Herrema's squawking at least has the merit of sounding like it belongs to the music it fronts.

Alan Licht, the leader of New York's Run On, and avant-rock's answer to Jeff Beck, filled in for Hagerty (playing a very un-indie Stratocaster). He seemed out of place: His lead lines were too impeccable, the skronky chords too tasteful, the picking too clean. But he rocked the audience, which wasn't difficult considering the two opening acts, and Herrema's obvious enthusiasm made a positive impression on the crowd.

In terms of basic entertainment, Hagerty wasn't really necessary. That may not be something he wants to hear, but it conforms to the indie principle that says the music is more important than the person. A real lo-fi artist would take it as a compliment.