Snappy, revved-up, machine-age urbanity, unburdened by centuries of stifling European tradition, vulgar and unschooled, but brash, visceral, and très, très moderne: All this is what America symbolized to the French in the early decades of the 20th century. The most thrilling musical manifestation of this envy was Amériques (1921), a sizzling, raucous, 25-minute work for huge orchestra by Edgard Varèse (1883–1965), who was born in France but lived in the U.S. after 1915—the same journey taken by Ludovic Morlot, the Seattle Symphony's new music director, who's conducting it this weekend. Hints of jazz are not hard to hear among the work's ominous crashes and thumps (gunshots? a garbage can overturned in an alley?) and brooding solos—one sultry brass lick against a haze of strings could be a hooker or a gumshoe loitering under a streetlamp. The nine-player percussion contingent includes a police siren—heard typically just after the music's most riotous climaxes, as if the cops were showing up to investigate the disturbance. Resemblances to Stravinsky's The Rite of Spring (1913), which opens this weekend's concerts, are fairly frequent and obvious, but the atmosphere is film noir rather than primitive Russia; some relentlessly pounding passages come off as a sort of street-gang reflection of The Rite's tribal dances. Varèse apotheosizes not just America the place, but also America—the "New World"—as a metaphor for unexplored musical territory (which is why the title is plural); the work's wildly imaginative and unprecedented sonic chaos, both celebratory and disturbing, still sounds ballsy after decades. In a way Amériques is the dark side of An American in Paris (1928), Gershwin's nostalgic cityscape stroll, the third work on these concerts. That Gershwin's view of France and Varèse's of America should share an evening makes perfect sense as Morlot's greeting to his new home. Another connection: Frank Zappa, whose Dupree's Paradise the SSO played last weekend, was one of Varèse's most outspoken champions, adopting the avant-est-of-the-avant older composer's battle cry as his own: "The present-day composer refuses to die!"