Concrete isn’t the most practical material for a speaker. It's heavy, and its acoustic properties are usually pretty terrible. “Ever been in a big concrete room?” asks Drew Stone Briggs. “There’s a lot of echo. Echo on the inside of your speaker is a bad thing.”

Briggs is chief product officer at the upscale audio company Master & Dynamic, where he’s spent the past two years developing—wait for it—a concrete speaker. Here's the thing, though: M&D's hefty new cabinet isn't bad. In fact, the MA770 sounds damn impressive. But to get to a place where concrete enhanced its sound, instead of hindering it, Briggs and his team had to rethink both the shape of the speaker and the material itself.

All speakers aim to do the same thing: Deliver as powerful a sound as possible while minimizing aural impurities like rattle, humming, and clicks. Limiting energy transfer between the speaker driver and its enclosure is crucial. "You want all that energy to be pushed out as sound," Briggs says. Lightweight materials like wood and plastic, while common in high-end cabinets, are susceptible to vibration. But by thickening the cabinet's walls and adding internal braces, manufacturers can keep the enclosure nice and rigid.

Concrete, by contrast, is naturally stiff. This meant M&D could replace the interior bracing found in conventional speakers with a soft, insulating material. “The enclosure isn’t imparting anything into the sound, so you have very low distortion” says Brian Biggott, head of strategy at M&D. Suspending the speaker cone and electronics in a virtually empty cavity promotes sound quality and realism.

But while concrete’s rigidity is good for minimizing vibration, it's terrible at taming echoes. M&D needed concrete that retained stiffness but also minimized reverb. To do this, they mixed the concrete’s rock and stones with a handful of polymers (the company's designers won’t reveal their recipe), which created a material that absorbs echoes like a rock-hard pillow.

Material in hand, M&D tapped architect David Adjaye to craft the speaker’s angular shape. Adjaye, the esteemed designer behind the new National Museum of African American History and Culture, grew up building speakers in North London out of wooden boxes filled with concrete ballasts to reduce vibration. For the MA770, Adjaye wanted to put the material to use, creating an unorthodox silhouette that reflects the speaker’s function.

From the side, the shape of the cabinet mimics the sound emanating from the speaker. The tapered back expands to a wide, flat surface in the front. It’s beautiful and architectural, but it also produces superior sound; by minimizing the area in the back of the speaker cabinet, you’re maximizing the sound that gets pushed out. “Everything that goes backwards creates reverberation,” he says. “You’re trying to deaden that as much as possible, which is really the intelligence of the design.”

Acoustic nerdery aside, the MA770 is, frankly, just really nice to look at. Adjaye designed an etched metal grill to cover the speaker, and the device’s buttons make for a tiny control panel across the bottom. As for heft, the MA700 weighs in at just under 40 pounds. This is M&D's first speaker, so the company wanted to make a statement piece. “I didn’t want something small and portable,” says M&D CEO Jonathan Levine. The thing had to look, sound, and even feel luxurious—which translated to a rather involved manufacturing process. Each speaker is cast and cured in a mold, which is then broken in half and removed to create a seamless effect. Afterwards, technicians shape the hunk of concrete with a rotary tool and hand-buff it to achieve a subtle grainy texture.

It's not a simple process, but Levine says intricacy is inherent in creating something new. “As a company we design first and then we worry about how we're going to build it later,” he says. Spoken like a company who's speaker boarders on sculpture.