Sunlight pours in through the plate-glass windows of Bull City Records as a few lunch-hour browsers leisurely investigate the shop’s wares. It’s midafternoon in early July, and the heat of summer has not yet become insufferable. Up front, near the register, a member of a local hip-hop collective flips through the used bins in search of sampling material. A trio in their early twenties combs through hefty rows of new arrivals. At the front desk, Chaz Martenstein fields a phone call about his stock of MC5 recordsa commonplace occurrence here.

“We have all three,” he says. “Kick Out the Jams, Back in the USA, and … High Time.” Martenstein hesitates for a moment before completing the listhe’s human, not a walking encyclopedia. Then he does something that the average record store proprietor isn’t likely to do.

“Hang on,” he tells the caller. “Lemme just check.”

Putting down the phone, Martenstein slips from behind the counter and over to the place where MC5 records are kept. He returns to deliver the good news. It’s not a huge act, but it shows heart. And while he genuinely would hate to provide a customer with faulty intel, Martenstein admits later that it wasn’t entirely selfless.

“I like to know,” he says. “It’s just that thing where your brain kind of likes you to know your stock. My own mentality,” he adds with a chuckle.

Over the past decade, Martenstein’s mentality has helped his Bull City Records become what is now the longest-running record store in Durham. Martenstein has enlisted a host of friends to help him celebrate the shop’s eleventh year of business with a two-day festival, Friday night at The Pinhook and Saturday at Ponysaurus Brewing Company. The roster will be decidedly Chaz-centric, from Superchunk on down.

“I called in all my favors for this one,” he laughs. “I figured if I could get [Superchunk] it would be a huge achievement. And Pipe, to me, was just a natural fit. It was, ‘What would a dream bill of mine be?’”

So the expert curator curated his own music festival, with each choice reflecting Martenstein’s deep love of each act’s music along with a deeper rationale. He wanted bands that had played the early in-store shows in his old space, like the Dirty Little Heaters, plus members of Megafaun and Solar Halos. He convinced a couple of his favorite local outfits, Last Year’s Men and The Dry Heathens, both currently on hiatus, to reunite for the occasion. Every band on the roster has a connection with the Triangle and the shop, even the Seattle-based Happy Divingguitarist Will Anderson lived and played in the area a few years back and just happened to be passing through this weekend.

This victory lap might have seemed unlikely in 2005, when Martenstein set up shop above a Mexican restaurant on Perry Street in Durham. The location was conspicuously off Ninth Street’s main drag, and only accessible via a narrow, rickety staircase that was more foreboding than is ideal in a retail situation.

“It was a cool spot and it had character,” Martenstein recalls. “And if you knew the space, it was a comfortable space. But it was hard getting first-time visitors.”

Nevertheless, customers ventured up the creaky stairs, and many spread the word after they came back down. Durham’s music community showed up, too. Early on, in-store performances helped cement the store’s presence. Eventually, those shows led to the formation of Bull City HQ in 2007, a multi-use public space overseen by Martenstein and a handful of area musicians and artists. At a time when Durham was woefully lacking in small venues, BCHQ helped give numerous near-unknown musicians a start. Martenstein also teamed up with other sourcesWXDU, Duke Coffeehouse, and the now-defunct Troika Music Festivalin continued efforts to stir up the city’s concert scene.

Kym Register, who owns the Pinhook, and who takes the stage with Bad Friends for the BCR party Friday night, co-founded BCHQ with Martenstein. She describes her friend as morally driven.

“He gives a really big shit, for lack of a better term. He cares about this town a lot,” she says.

Martenstein says music found him at an early age. As a child in Richmond, Virginia, his parents gave him a portable radio, which he carried around and kept tuned to oldies radio even as he played with his toy trucks. When he was about fifteen, the college radio station at the nearby University of Richmond gave him his first glimpse of the depth of it all.

“There was this underneath,” he recalls. “Indie rock, college rock, art rock. I got very obsessed with that.”

He took to haunting used-CD stores, looking for the bands he’d heard on the radio, and fell in love with the hunt itself. Around then, he decided this was the world he wanted to occupy. “I just decided it was worth working hard to move toward,” he says.

Bull City Records’ reputation is built upon that kind of commitment. It’s the kind of place where you’re not afraid to ask questions or risk seeming dumb. Martenstein’s belief in customer service is what makes the difference.

“It’s as important as your stock, if not more important in the music world, where it’s not any secret that pretty much a hundred percent of my stock is available for freeor notonline,” he explains. “You have to give people a reason to come in.”

For Martenstein, that relates to the way he talks to people, learning their names and remembering their preferences. “Customer service is that little thing that gives people that reason to come back,” he says.

Once he settled into the new space in the fall of 2011, the store’s fortunes swiftly improved, aided by a ground-floor location and an adjacent parking lot. The current Hillsborough Road storefront is easily accessible for walking and driving customers. And the resurgence of vinyl in recent years has been a major boon.

Ultimately, though, what distinguishes and sustains Bull City Records is the goodwill that Martenstein engenders, one customer at a time.

“In a music scene where knowing the right people can be important, he’s one of the most genuine humans that I know,” Register says. “He just doesn’t seem to feed into that. He does it because he really likes it or wants to. There’s nothing fake about that guy.”

Martenstein is nothing like the stereotypical record store owner. Mac McCaughan, who worked in record stores prior to forming Superchunk and Merge Records, confirms that Martenstein’s approach isn’t always a given.

“There’s kind of an old trope, at least from when I was working in record stores in the eighties and nineties, that record store employees are grumpy and snobby and they think they know better than the customer,” McCaughan says. “I think Chaz does a good job of actually listening to the customers and finding out what they want, what else is going on around that artist or scene. I think that’s the main reason he’s built up such a loyal customer base.”

Still, Martenstein proudly calls High Fidelity, Nick Hornby’s novel with surly record store employees at its center, one of his favorite books and movies. On the eve of opening Bull City Records, Martenstein’s brother gave him a copy of the book signed by the author. Hornby wished the new record-store owner good luck, adding a foreboding, “You’re going to need it.”

But as it’s turned out, luck hasn’t played much of a role in the success of Bull City Records. The real reason for that lies closer to Martenstein’s own modest explanation for his success.

“You gotta work hard and like what you’re doing,” he says.