'WE ONLY GOT an hour left," DJ Premier announces to the dwindling crowd. It's 3 a.m. at the Sound Factory, and the audience has patiently waited for Premier – one-half of Gang Starr and an underground icon to a generation of hip-hop listeners – to hit the stage. Now, after several opening acts and a raft of DJs both local and national, Premier has finally emerged, only to confirm that he won't be spinning the 2.5 hours promised by the event's promoters. "I'm just gonna play some shit, and if you like it, you like it," Premier says. "If you don't, you don't." With that, Premier spends several minutes tweaking with the mixer and two turntables, calibrating them for maximum effect.

Finally he puts on a record, the opening strains to Gang Starr's "The Question Remains" surge through the club's speakers, and the crowd goes wild. B-boys go out of their heads, leaping up and down, screaming indecipherable phrases, and whipping their heads back and forth faster than a punter at a System of a Down concert. A few members of the local B-girl crew Anti-Gravity Queens spark up a break-dance circle and bust out their best moves, while other women in the crowd oscillate with the fury of a blade of grass caught in a cyclone. Meanwhile, Premier plays several recordings he produced, including the Lox's "Recognize," Group Home's "Supa Star," and Gang Starr's "You Know My Steez," before cueing up popular rap hits by Snoop Dogg and Jay-Z.

At one point he beat-juggles Jay-Z's "U Don't Know," expertly cutting between two vinyl copies of the song to create a seconds-long display of the joys of repetition. But for the most part Premier doesn't even bother to blend the records during his truncated set, instead simply playing a record for a minute and then sloppily cutting to the next one. The crowd doesn't care; everyone's too lost in the music Premier's playing and the novelty of being in the presence of a genuine superstar, one of hip-hop's few certifiable geniuses.

The DJ as producer

"I missed his set," DJ Design says when asked what he thought of Premier's performance, protesting that he had to leave well before Premier's early-morning appearance, but "I think he's really developed as a DJ. That's what I'm trying to achieve – what he did on record."

Design was one of Premier's opening acts that night. Performing with his band Foreign Legion, Design cued up instrumentals for "Bring That Shit" and "Happy Drunk," then gleefully cut them up while MCs Peter Parker and Prozack rhymed, often shouting out key phrases like seasoned sidemen. Design closed "Bring That Shit" with a flurry of scratches, bringing the song to a furious climax.

Yet in spite of his onstage prowess, Design considers himself a producer. Since his first production credit on Rasco's 1998 single "What It's All About," Design has gone on to record a full-length and several 12-inch singles with Foreign Legion; remix tracks for the Beastie Boys, jazz pianist Bob James, and L.A. avant-rap group Darkleaf; and drop two solo break albums, Gather Round and Hookie and Baba Flake Breaks. "People in the industry perceive me as more of a producer than a DJ," Design says, adding that he doesn't get as many DJ gigs as he thought he would.

The art of DJ mixing – from scratching and blending to programming a set that responds to and builds a crowd's emotions and desires – plays a major part in how Design constructs his music. "While I'm onstage performing with my group, if either Peter or 'Zack have a punch line, I'll drop the music out with a fader, then bring it back in on the snare or a drum kick," he says. "When I produce, I think of the punch lines, and I drop certain [music elements] out accordingly."

Like rock 'n' roll, DJing has grown into an elaborate value system. It refers to turntablists who scratch and manipulate turntable equipment, coaxing bizarre sounds from a record's grooves; has been appropriated by producers who make beats with repetitive 4/4 rhythms similar to godfather of hip-hop Kool Herc's beloved "breaks"; and is used by sound artists who create music with computers, sampling equipment, and even analog instruments. More than a signifier for those who are proficient in the art of playing records, it reflects a person's ability to collate different sounds, both improvised and preexisting, into a mixture, a work of art to be absorbed. For hip-hop producers like Design, the word "DJ" not only sounds cool but also connects modern-day producers with hip-hop's gloried origins.

Perhaps it's for those reasons that studio-bound masterminds like Dan the Automator (best known for his work with cartoon rock band the Gorillaz, Deltron 3030, and Handsome Boy Modeling School) still play club gigs from time to time. Earlier this spring he spun a set of old-school hip-hop, scratching a dismissive "Bullshit!" from B-Real over an instrumental version of Cypress Hill's "How I Could Just Kill a Man," before a Gorillaz show at the Warfield. When asked why he got into DJing, Dan the Automator answers, "I just loved music. By the time I figured out what I wanted to do – I didn't want to be in a band or anything – I figured I'd DJ, because I really didn't understand the producer's role at the time."

Unfortunately, as De La Soul once rapped, "Everyone wants to be a DJ," and the Bay Area is full of would-be mix masters spinning at clubs, house parties, weddings, bars, parks, and other spaces. "It creates a huge mess," Design complains. "You have to filter out all this bullshit to get to someone who's actually serious about it." For many producers, making their own tracks for public consumption, rather than simply spinning records alongside everyone else, is more exciting and creative and a way to stand out. "I like DJing and stuff, but I really want to be in my house, in my studio, producing stuff that's more challenging for myself," Design says.

The producer as artist

"When I sit down and make a record, I'm trying to better my peers," DJ Shadow, auteur behind such hip-hop classics as Endtroducing and the What Does Your Soul Look Like EP, says during a brief interview at Village Music in Mill Valley. "If you're going to innovate, that takes years of discipline. The sampler is my instrument."

Like Dan the Automator, Shadow is often misperceived as a reclusive figure, when in fact he spent years spinning in nightclubs. "I always consider myself a DJ first, because I couldn't have been what I am without having been a DJ," Shadow says. Growing up in Davis, he was known as "the scratch guy" among his friends. He started DJing at clubs in 1993 and hosted a short-lived mix show, Hardcore Hip-Hop Show, on KMEL-FM. "I was playing accessible, danceable hip-hop," he says.

Nowadays, Shadow says, his performances tend to be more "conceptual, trying to shift people's paradigms a little bit instead of trying to crab scratch faster and faster." In 1999 he performed two "Brainfreeze" concerts with turntablist and Jurassic 5 producer Cut Chemist, spinning a set wholly made up of rare funk 45s; its success led to two heavily bootlegged CDs and another tour, last year's "Product Placement." When he performs solo, he usually sticks to his own recordings, weaving tracks like "What Does Your Soul Look Like Pt. 2" and "Midnight in a Perfect World" into an hour-long megamix. "I basically treat my catalog as my mix source," Shadow says, adding that he'll make vinyl test pressings of "every conceivable combination of a song" before going out on the road, including an instrumental, an a cappella, a "drumapella, all music no drums, this piano sample next to this sample here, etc."

Since his remix of Lifers Group's "Real Deal" backed with the Steinski homage "Lesson 4" led to hip-hop critics proclaiming him a prodigy in 1991, Shadow has primarily focused his energies on producing. He recalls contributing several uncredited beats to Oakland rapper Paris's 1992 album Sleeping with The Enemy and sending demos to New York luminaries like Funkmaster Flex ("I remember he'd be like, 'Yo, it starts off cool, but then you get nervous!' ") and rap labels like Tommy Boy, Big Beat, and Profile, all with little or no success. "Keep in mind that I didn't even have a sampler yet," he says. "I was doing everything on a four-track recorder, and it just didn't sound to par. I think a lot of people really wanted to hook me up."

Finally, British label owner James Lavelle invited Shadow to record for Mo'Wax in 1994 (Shadow has since moved on to MCA). Two EPs, Influx/Hindsight and What Does Your Soul Look Like, and two full-lengths, Endtroducing and Preemptive Strike followed – the latter compiling the first two EPs, one new track, "High Noon," and a limited edition "megamix" CD by DJ QBert. On those recordings, Shadow painstakingly assembled samples from other records into long minimalist epics filled with drum breaks that fluctuate, changing pitch and time patterns and creating a rhythmic bed as dynamic as one produced by a "live" musician. Endtroducing, in particular, was widely acclaimed as an unrelenting instrumental journey into Shadow's various neuroses and fears, an album as emotionally overwhelming as Pink Floyd's Dark Side of the Moon.

For his new album, The Private Press, Shadow deliberately chose to shift emphasis away from the drums, often leading a song off with a plaintive bass line ("Mongrel ...") or melody ("Giving up the Ghost"). Interspersed throughout are snippets of various home recordings, lending the album a warmth that sets it apart from the intense and highly personal Endtroducing. Shadow says he "took in more music [before preparing to make the album] than at any other point in my life, because I needed constant influence."

"I think it's more varied," Shadow says. "I cover a lot more musical ground. The lights are lighter, and the darks are darker." True, The Private Press sometimes changes hue in a single track, like when MC Lateef the Truth Speaker's guest appearance on "Mashin' on the Motorway" abruptly mutates into "Blood on the Motorway's" goth-inspired melancholia.

But it also contains plenty of familiar archetypes. "Un Autre Introduction" is a turntablist-style cutup that harks back to an old Shadow track, "Last Stop," while the antiwar lament "Six Days" evokes Endtroducing's "Stem/Long Stem," albeit with a vocal sample. "It would take me years to replicate any song I did," Shadow says. "It would be like rolling the same combination of dice." However, in spite of the limitless amount of samples available to him, Shadow's distinctive production style emerges all the same.

"To a certain degree, what you do depends on what comes into you," Shadow says. "Then what you do with it once it's there, that's the difference."

Perhaps it's to be expected that producers like Shadow are faced with the same quandaries as any other musician: how to innovate and evolve in spite of a panoply of studio techniques available to them, as well as their own musical biases and personalities. Far away from the nightclubs they once played as DJs, they still face the enviable task of mixing old records and classic turntable tricks into hip-hop art.

DJ Shadow performs Tues/11, 9 p.m., Fillmore, 1805 Geary, S.F. $25. (415) 346-6000.