The view from the choir loft is impressive: a huge nave swelling with music, with wisps of smoke wafting from the sanctuary. The upturned faces of the young congregation seem transported. But then a snarling guitar chord rips rudely through the gathered, and the crowd at the former St. Ann's Catholic Church erupts. The liturgy being celebrated in this century-old house of worship isn't High Mass but the band Don Caballero's gig at Pittsburgh's church of rock-and-roll.

Let us play.

Esquire magazine raised eyebrows when it named Pittsburgh the No. 1 "City That Rocks" in its April issue: With few breakout national bands and no single street of dreams for its music scene, this post-industrial town seemed an unlikely candidate. Where were the clubs that spawned the ranking? To investigate, we turned to a local bass player, Sara Radelet, who suggested an energetic odyssey that kept us crisscrossing the city's many bridges over several spring nights. The common club denominators we found were high-decibel sound, low-watt lights, tattoos and 20-pound key chains, and a truculent refusal to cover Top 40 radio.

"It's a band and guitar town -- lots of great guitar players," says Joe Grushecky, a gray-haired veteran of the local scene. Says fan Nick Ker, who's observed local acts for more than a decade, "It's raw, passionate stuff. It's authentic and original."

Pittsburgh may be the most iconoclastic city in America when it comes to rock venues. Undiscovered, paid-in-beer local bands play settings from former churches to museums (the Andy Warhol) to bowling alleys (Arsenal Lanes, every Monday night). But it's appropriately divey dark bars that host most of the weekend action.

Esquire anointed Mr. Small's, the desanctified St. Ann's a few miles upriver from downtown, as one of the city's best places to hear rock. The club's giant space feels sort of overgrown and adolescent, like many in the all-ages audiences. However, Mr. Small's reputation is growing as quickly as its fans are. It hosted Ryan Adams for a month of rehearsal before his tour last summer with the Rolling Stones, and rapper 50 Cent and the Black Eyed Peas have recorded new work in its studio.

The club draws an attentive, young, mostly male crowd, whose intensity is only partly due to Mr. Small's lack of a liquor license. The shared buzz is the "contact high" promised by Don Caballero drummer Damon Che as he drives the band's avant-rock, all-instrumental sound. Guitars layer a syncopated melody on top of Che's tempo for weird harmonies as they crash into "Palm Trees in the [Bleep]ing Bahamas."

Despite the rude title, the music is brainy, almost ethereal. At midnight, we filter out of the club -- double-doored to keep the noise from the neighbors -- and walk down a cobblestoned hill through the town of Millvale. Changing fortunes in this blue-collar town, former home to a saw blade factory, have brought it new buzz-saw rhythms.

For our Saturday night expedition, we ignore the boardwalk atmosphere of the city's Strip District, whose warehouses and lofts flank dance clubs for the singles who spill out onto Penn Avenue. We flee a half-mile east to find the 31st Street Pub, sulking in the shadow of the bridge that shares its name.

The $5 cover charge to the black-painted taproom buys us any seat in the house; at 10 p.m., we're absurdly early arrivals.

But inside we find Radelet's band unpacking amps under the Iron City neon lights. Pain Dogs' influence is "punk rock-and-roll, in the vein of Screeching Weasels," explains guitarist Bradley Simon. But punk doesn't pay, so the three band mates keep their day jobs: Radelet as assistant director of the Mattress Factory, a nearby museum of installation art; drummer Keith Beck as a software engineer; and Simon, a shaved-headed mountain of a social worker turned grad student. They race through a dozen numbers and nearly as many beers before ceding the tiny stage to the Mud City Manglers and retiring to the bar for $2 drafts.

Hundreds of toy skulls stare down from above the bar as the Dogs preview the following act.

"They're one of my favorite bands," Simon says approvingly. "They've got good energy and a real mean stage presence."

Confirming their reputation, the Manglers blast into garage rock that makes our plastic glasses reverberate in our hands. Motioning the crowd forward, vocalist Ted Tarka taunts, "Don't act like we have lice or something!" "But you do!" a gleeful voice responds. Even the skulls are grinning.

Ears ringing, we adjourn to the South Side, crossing yet another river (this time, the Monongahela). It's a favorite spot for Grushecky, who's played every club along East Carson Street here.

"To me, that's like the coolest section of Pittsburgh," he says fondly. "There's a real mixture of stuff going on -- ethnic flavor, old architecture, shot-and-beer bars."

We find all three elements at the Smiling Moose, recommended by the Pain Dogs.

En route, as we pass the American Serbian Club and the Ukrainian Home, I wonder briefly if this Moose is a reincarnation of one of those proud immigrant fraternities.

The club turns out to be a narrow, old-fashioned storefront, but the crowd is indeed smiling. With cheap drinks and no cover, this Moose packs 'em in, especially on Saturday nights. At the rear of the back room, the Weekend Warriors have crammed so many amps on to the little stage that punk guitarists Zack Sovek and D.J. Riel are forced down to the floor. As the crowd builds, the pool table becomes seating for those with long tattooed legs, and the distance between listeners and singers shrinks to the length of a fan's skirt.

We rescue our hearing around the corner, at the city's most sophisticated rock venue. Club Cafe, with a glowing glass-topped bar and comfy banquettes, boasts the city's most eclectic bookings, from touring cellist Matt Haimovitz to soloists from Soul Coughing. Tonight, fittingly, there's glam rock from local faves the Science Fiction Idols. Thanks to the superb sound system, we realize we can actually decipher the lyrics sung by vocalist Bobby Lamonde. It's still rock, and there's still beer, but there's also food. The atmosphere is subtly relaxing. Then the inevitable droop sets in.

We begin a rainy Sunday morning -- okay, early afternoon -- with an attempt at a virtuous brunch. The funky Zenith Tea Room promises a vegan buffet, so we duck into its front room, a thrift-shop welter of religious statues, rotary phones, bowling balls and duckpins. We wait for a table. But a dispiriting plate of cool eggs and rice leaves us hungry, so we head back out to Carson Street in search of a real meal.

Happily, we find breakfast-all-day at Tom's Diner. No vegans here. We stuff ourselves with life-giving French toast, bacon and home fries for 10 bucks.

With Pittsburgh breakfasts, if not bands, it's sometimes okay to go back and cover the oldies.

Sara Radelet, a bassist for the band Pain Dogs, performs at 31st Street Pub in Pittsburgh's Strip District on a recent Saturday night. The club is one of the city's many venues for live rock. The crowd gets up close with the band Weekend Warriors during a set at the Smiling Moose, a converted storefront on Pittsburgh's South Side. The city's rock clubs inhabit industrial lofts, converted warehouses, even desanctified churches.