For Nathan Frankel, music and architecture first collided when he was six and tried to play a violin. “The story goes that I threw it against the wall,” he says. “It was not a successful start.”

But encouraged by his father—a classical-music patron and sometime musician—Frankel picked up the pieces and kept practicing. He spent summers at Interlochen Arts Camp in Michigan, and as an undergraduate he was concertmaster in the Brandeis University symphony orchestra. Today, he’s almost certainly the only concert-level amateur violinist in America who also runs his own scrap-metal export business.

In 2008, when Frankel began to envision a custom-built home for himself, he knew he wanted two elements: supreme quiet, so he could focus on listening to and playing music, and a space where others—sometimes many others—could do the same. With architect Noah Walker, principal of the Los Angeles–based Walker Workshop Design Build, Frankel has created a guesthouse high in a Beverly Hills canyon, featuring a living room that doubles as an 80-seat concert hall.

Designing the hall, it turns out, wasn’t as tough as finding a quiet site on which to build. “That’s not impossible to find in Los Angeles,” says Frankel. “We have hills—it’s not like New York City. But for the most part, in the hills, you end up with a small house that juts over a cliffside because there’s so little usable land, and you’re peering over your neighbor.” Not ideal when your house is going to include a concert venue.

The perfect parcel of land finally presented itself in the form of a 3.5-acre hilltop plot, where in the 1970s a previous owner threw debauched parties prowled—neighborhood legend has it—by the likes of Bob Dylan. One can see why superstars might feel free to let loose here: Surrounded by canyon views and greenery, it feels more like a remote state-park outpost than private land just four miles from Rodeo Drive. Still, the parcel wasn’t without its downsides, like a narrow access road that made the fire department nervous—Frankel allayed their fears by installing a fire hydrant on the property—or the stands of protected walnut and coast live oak trees spilling down the hillside, which by law can’t be damaged or removed.

For both client and architect, though, trees were less an obstacle than an inspiration for the open, minimalist two-bedroom home. “This is very much a tree house in a lot of ways,” Walker says. Taking cues in part from Kyoto’s Entsuji Temple and its long views of the countryside, he designed almost every room with giant windows—made with especially clear, low-iron glass—framing the tree canopy. He deployed a dark interior color palette to match the oaks’ deep greens and grays. Shortly after construction began, he even shifted the footprint of the house to save a eucalyptus tree he’d originally planned to uproot. Shooting up a mere foot from the back deck, it has become, Walker says, “this wonderful sort of feature…it really starts to shape your experience of the house, how it’s just nestled into the trees.”

Not surprisingly, the architect saved the most impressive natural display for the living room, which doubles as a concert hall. The space was built around the bones of a 1940s-era barn that came with the property; Walker added ten feet to the structure’s length, extending it toward a stand of oaks. Then he installed a floor-to-ceiling window—three massive panes of glass, taking up almost an entire wall—to create a spectacular wide-screen view of the trees that serves as the backdrop for the musical performances.

“That is about as magical as it could have ever happened for me,” says Frankel, gesturing toward the window. “At Interlochen, we would play music and practice in cabins that were in the woods, or at the side of a lake. It was that sort of integration of nature and music.”

Less immediately noticeable in the living room are the ingenious details that allow it to transform into a performance space. Folding chairs and musical gear can be stored in an area beneath the floor. Extra HVAC ducts are tucked away around the edge of the room, ready to cool a large audience. The rear half of the space is 18 inches higher than the front, creating a cozy pit for an L-shaped sofa and allowing for raked seating when it’s concert time.

But the biggest question remained: Would live music sound good in here?

Frankel and Walker opted not to deploy sound baffling or special acoustic design in the space. In fact, Frankel insists all that’s needed is a rectangular room. “I’ve been to places that have, like, curved walls and glass and every conceivable material placed at the most odd angles, and there are still dead spots and sweet spots,” he says. “Then you go to a shoe box–shaped performance venue anywhere in Europe that was built 400 years ago, and no matter where you sit in it, [the sound] is perfect. It’s a rectangle—that’s all it is.”

One Monday night, Frankel proves it. He’s hosting a benefit performance by the celebrated Romanian violinist Alexandru Tomescu, and the first note the musician drags out of his Stradivarius raises the hair on my arms. The dozens of audience members packed into the room provide all the baffling necessary; it sounds fantastic.

Tomescu fires off “Caprice No. 24,” one of several Paganini compositions so mad and so fiendishly difficult to play, the composer was said to be possessed by demons. Senses swirling, I suddenly notice the globe lamps hanging above me reflected in the giant window behind Tomescu as he bows his instrument with a fury. Outside, above the coast oaks lit from below, there’s a full moon rising. And superimposed over all of this is a reflection of us, the audience. It is layers upon layers, the constructed and the natural and the human, all instruments in harmony.