SAN FRANCISCO -- The Jon Spencer Blues Explosion blew the doors off the

conventional concept of an in-store appearance Sunday afternoon at Haight Street's

Amoeba Records.

They were loud. They were hard. And they didn't care where they were.

Luckily for fans and, especially, others caught in the sonic cross fire, the busy record

store provided everyone with earplugs.

The genre-defying New York City trio, fresh from a sold-out show at the Fillmore

Auditorium the night before, stormed the makeshift stage at the sprawling record store

promptly at 1 p.m. They screamed "Howdy kids!" into their mics and began a musical

attack that lasted for the better part of an hour.

Opening with a loud, garage-style "Get Over Here," from 1996's Now I Got Worry,

the band immediately turned the quiet warmth of the San Francisco afternoon into a

screaming, nasty little hootenanny right there in the record aisles -- from the folk-rock

section to the R&B and back to the modern-rock used-record bins at the far end of the

shop.

Fans and curious spectators packed the bowling-alley-turned-record-store all the way to

the back. Among them were folks who looked as if they ordinarily would prefer not to be

awake, much less out of the house, at that hour of the day. Many kept their sunglasses

on and shook their hips within the narrow confines of the record-store pathways.

"He gives everybody what they want," Jarrett Deshazer of Tucson, Ariz., said. "I mean,

look at this guy. He's got it all."

Ripping through some newer stuff, such as "I Wanna Make it All Right," from their latest

release, Acme, and also allowing for a few audience requests, including

"Bellbottoms" and "Two Kindsa Love," the Blues Explosion eventually even had the

store's security caught up in the beat.

Fittingly, Blues Explosion songs rely heavily on the common blues themes of sex, sorrow

and sensuality. But the band's music is far more raucous than standard blues, with two

loud guitars and spare, harsh drumming that powers through the punk-edged sound.

That point, which the band emphasizes on its recent record, was driven home again and

again Sunday.

In fact, the band demonstrated a versatility that could challenge even the most fervent

lover of experimental music, with each song incorporating a different feel than the one

that came before it.

Watching Spencer -- who was clad in tight, black-leather pants, wore his guitar slung low

and just oozed cool -- it was hard to imagine a more consummate rock showman. Based

on the sea of rapt faces gazing up at the stage, he seemed to have everyone under his

spell.

The singer/songwriter jumped and swung himself around the stage, punctuating his

guitar work with kicks and shouting "Sock it to me!" and "Feels good!" If you listened

carefully, Spencer managed to work the words "blues explosion" into just about every

song.

Second guitarist Judah Bauer, who also exhibited a certain rock cool, played flashy and

hard, using his effects pedals with speed and agility, transforming the band's sound with

just the tap of his foot. His guitar ground out everything from dirty blues to slick funk to

crunchy, '70s-style arena-rock.

As it is known to do, the band careened all over the musical map, combining delta blues

with garage, punk, hard rock and funk -- sometimes all in the course of one song.

"Vertical histrocity" is how Deshazer referred to it. "It's one of those postmodern phrases

which means that we've got it all now, and that, in this case, musicians can sample from

damned-near everything, every type of sound, and still pull it into something new," he

explained.

Drummer Russell Simins gave his spare, basic kit a serious working-over, providing a

loud, driving backbone for the music's wild changes.

The band wound the crowd up even more, with a theremin- and feedback-filled version

of "Talk About the Blues," as Spencer finally leaped off the stage and balanced himself

on top of a record display, screaming into the crowd that he felt good, real good.

People gasped and moved forward, seemingly desperate to touch Spencer, who was

perched right above them.

Then Spencer leapt back onto the stage, made a few final flourishes and marched off,

leaving the high-pitched theremin feeding back loudly and Simins and Bauer pounding

away on the small stage.

Eventually, they filed off as well, leaving just the theremin wailing in the background. As if

in a state of shock, some people took a few minutes to register the show's ending.

Then, as if on cue, they pulled out their store-provided earplugs and gathered

themselves together to head out into the blinding Sunday sunlight.

Those who left their eardrums exposed to the full force of John Spencer's Blues

Explosion are probably paying for it now.

It's guaranteed their ears are still ringing.