East Bloc's Top Underground Rock Bandk Tours the US. CZECHOSLOVAKIA'S PLASTIC PEOPLE

DRESSED in black, Czech rock star Milan Hlavsa is crooning: ``In a narrow street in Chinatown, a big Cadillac is cruising/ A beautiful girl sits inside, but maybe it is a man.'' Michaela Nemcova, the band's female vocalist, advances downstage at the Iron Horse Cafe here in Northampton. Through the crash of drums and guitars, the two Czech rockers chant in pounding syncopation: ``New York City! New York City!'' - a Bohemian rhapsody to America's Big Apple.

The Plastic People of the Universe, the Soviet bloc's most celebrated underground rock band, recently completed a sellout, coast-to-coast tour of the United States that included dates in New York, Boston, Chicago, and San Francisco. The group's US appearance, a significant event in East-West cultural dialogue, is among the most overt signs yet that glasnost is thawing one of the communist world's most orthodox regimes.

Last spring, after almost 20 years in the underground, the Plastic People (using a new name, Pulnoc, and four new members joining three from the original quintet) were permitted to make their first official appearance, at Prague's Junior Club. Now, less than a year later, the same musicians, including some who were once imprisoned for their music, have been touring the US with the permission of the Czechoslovak government.

``Five years ago, it would have been impossible to get out of Czechoslovakia,'' explained leader Milan Hlavsa through a translator, after three rousing encores in Northampton. ``In those five years there have been changes in the official attitude toward rock and roll. They now write about the Plastic People, about the legendary band, the Plastic People.''

The legend of the Plastic People goes back to the late 1960s, in those heady days of the Prague Spring, when the group emerged as Czechoslovakia's premier psychedelic rock band. The ``normalization'' of the Czech culture that followed the 1968 Warsaw Pact invasion forced the Plastics underground.

For the next two decades, the Plastic People engaged in a high-stakes cat-and-mouse game with Czech authorities. Concerts, held in isolated villages of the Bohemian woods, were announced by word of mouth a day in advance. Trekking on foot, sometimes for hours in rain and snow, fans would converge on a small tavern to watch the Plastic People perform. The police often arrived first; clubbings and arrests would follow.

In 1976, the Plastic People's saxophonist, Vratislav Brabenec, and band manager Ivan Jirous, were imprisoned in Prague's notorious Ruzine Prison for ``corrupting'' Czechoslovak youth with their music. The Plastic People soon emerged as one of Eastern Europe's most prominent symbols of underground resistance, despite the band's insistence that it was unpolitical: Mr. Jirous, for instance, claimed that Czechoslovakia's ``second culture'' was separate from, not opposed to, official culture. In the land of Franz Kafka, the unpolitical became political because it was unpolitical.

Official harassment of the Plastic People intensified in the late 1970s. ``In 1979, the state expropriated a farm where we had played a concert,'' Mr. Brabenec recalled in 1984. ``Last year they set fire to a house belonging to some friends just because the friends had let us play there.''

After a series of interrogations, during which Brabenec was beaten by the secret police, the saxophonist emigrated to Canada. Jirous repeatedly ran afoul of the law for his underground activities and has spent eight of the last 15 years in prison. Last October, he was again arrested for allegedly reading seditious poetry in public.

Incessant harassment exhausted the band; it also alienated the Plastic People from the underground rock scene, because, according to Brabenec, ``we carried police around with us like flies.'' By the mid-1980s, the Plastics were performing at most two or three concerts a year. But they found other means of reaching their audience. In the late 1970s, they began recording their music on tapes and circulating them among friends and fans. A number of these tapes, smuggled to the West, have been released as records in the West: ``Egon Bondy's Happy Hearts Club Banned'' (1978), a collector's item that sells for as much as $50; ``Passion Play'' (1980), a retelling of Christ Jesus' crucifixion; and ``Midnight Mouse'' (1988), the band's most recent, and listenable, album.

Early in 1988, hoping to break the cultural stranglehold, the Plastics made a bid for official recognition. Prague officials, realizing 20 years of persecuting them had failed, took the opportunity to co-opt the band. The state issued the musicians a license for public performance with one stipulation: that they change their name.

The decision to ``go official'' caused a rift among the musicians. According to Mr. Hlavsa, the band's drummer, Jan Brabec, ``said he would play as the Plastic People or nothing.'' Jirous, also refusing any quarter to official culture, distanced himself from the band. Hlavsa and the two remaining Plastics, keyboardist Josef Janicek and guitarist Jiri Kabes, regrouped with four new musicians to form a new ensemble, Pulnoc (Midnight).

``We did not rename the Plastics,'' Hlavsa insists. ``We created a new band, Pulnoc.'' Hlavsa selected the name to reflect the transformation of the Plastic People. ``Midnight is a very special time. It is when one day dies and another is born. And yet there is continuity. That is how it is with this band.''

As an ``amateur'' group, Pulnoc cannot receive money for its performances, but it is able to appear in state-run concert venues, to use state-owned equipment, and, most important, to tour abroad. Within months, Hlavsa was making arrangements with Czech 'emigr'es and Sightwaves, a New York-based concert agency, for a US tour.

On April 22, after overcoming months of diplomatic entanglements, Pulnoc had a debut in Chicago. Initially, Hope Carr, Sightwaves manager, hoped to capitalize on the Plastic People's former status as East Europe's most prominent (and persecuted) rock-and-roll band. But it quickly became clear the band could offer American audiences more than a voyeuristic glimpse at Soviet-bloc rockers unfettered. Pulnoc proved to be an astonishingly talented band.

Mixing classic rock with new wave and funk, Pulnoc has charmed its audiences and impressed critics across the US. The band brings a modesty to the stage that belies the explosive energy of its music.

The song ``Tiger, Tiger,'' based on the poem by the 19th-century British poet William Blake, is a rollicking dance number. Pulnoc's ``Song for Nico'' is a musical elegy for the female vocalist of Velvet Underground fame who died last year. ``We wrote this song in memory of her,'' Hlavsa explained. ``It is a song about life, about being trapped inside oneself.'' According to Bob Dubrow, a Boston-area disc jockey, Michaela Nemcova's rendering of the song recalls the ``same icy demeanor'' of Nico.

By the time Pulnoc arrived in New York, the word was out. Among the SRO crowd at the Manhattan club PS 122 were many of New York's leading pop music critics. Robert Christegau of the Village Voice claimed that the Pulnoc concert was one of the most significant concerts of the past decade. The next evening, New Yorkers were lined up down First Avenue hoping to see the band.

``The audience and media response has been incredible,'' says Sightwaves manager Hope Carr. ``They are getting more attention than they ever could have imagined.'' She pauses, then adds thoughtfully. ``After 20 years in the underground, they certainly deserve it.''