Graphene has long been touted as a miracle material that would deliver everything from tiny, ultralow-power transistors to the vastly long and ultrastrong cable [PDF] needed for a space elevator. And yet, 13 years of graphene development, and R&D expenditures well in the tens of billions of dollars have so far yielded just a handful of niche products. The most notable by far is a line of tennis racquets in which relatively small amounts of graphene are used to stiffen parts of the frame.
Ora Sound, a Montreal-based startup, hopes to change all that. On 20 June, it unveiled a Kickstarter campaign for a new audiophile-grade headphone that uses cones, also known as membranes, made of a form of graphene. “To the best of our knowledge, we are the first company to find a significant, commercially viable application for graphene,” says Ora cofounder Ari Pinkas, noting that the cones in the headphones are 95 percent graphene.
During an interview and demonstration in the IEEE Spectrum offices, Pinkas and Robert-Eric Gaskell, another of the company’s cofounders, explained graphene’s allure to audiophiles. “Graphene has the ideal properties for a membrane,” Gaskell says. “It’s incredibly stiff, very lightweight—a rare combination—and it’s well damped,” which means it tends to quell spurious vibrations. By those metrics, graphene soundly beats all the usual choices: mylar, paper, aluminum, or even beryllium, Gaskell adds.
Graphene’s high damping factor reduces unwanted speaker-cone movements, resulting in more precise sound, the company says.Gif: ORA Sound
The problem is making it in sheets large enough to fashion into cones. So-called “pristine” graphene exists as flakes, perhaps 10 micrometers across, and a single atom thick. To make larger, strong sheets of graphene, researchers attach oxygen atoms to the flakes, and then other elements to the oxygen atoms to cross-link the flakes and hold them together strongly in what materials scientists call a laminate structure. The intellectual property behind Ora’s advance came from figuring out how to make these structures suitably thick and in the proper shape to function as speaker cones, Gaskell says. In short, he explains, the breakthrough was, “being able to manufacture” in large numbers, “and in any geometery we want.”
Much of the R&D work that led to Ora’s process was done at nearby McGill University, by professor Thomas Szkopek of the Electrical and Computer Engineering department. Szkopek worked with Peter Gaskell, Robert-Eric’s younger brother. Ora is also making use of patents that arose from work done on graphene by the Nguyen Group at Northwestern University, in Evanston, Ill.
Robert-Eric Gaskell and Pinkas arrived at Spectrum with a preproduction model of their headphones, as well as some other headphones for the sake of comparison. The Ora prototype is clearly superior to the comparison models, but that’s not much of a surprise. The other units sell for about $100, while the Ora headphones will have a suggested retail of $499 when they are in production, Pinkas says. (On Ora’s Kickstarter page the headphones are offered as a bonus for pledges ranging from $199 to $350.)
Even given that higher anticipated cost, the headphones do not disappoint. In the 20 minutes or so I had to audition Ora’s preproduction model, I listened to an assortment of classical and jazz standards and I came away impressed. The sound is precise, with fine details sharply rendered. To my surprise, I was reminded of planar-magnetic type headphones that are now surging in popularity in the upper reaches of the audiophile headphone market. Bass is smooth and tight. Overall, the unit holds up quite well against closed-back models in the $400 to $500 range I’ve listened to from Grado, Bowers & Wilkins, and Audeze.
Consumer headphones may be just the beginning for Ora. Pinkas tells me that the firm is in negotiations now with an assortment of major smartphone, tablet, smarthome-speaker, hearing-aid, and augmented-reality companies that are considering the possibility of incorporating the graphene-cone speaker into their offerings. For these companies, the advantage of the graphene speaker is not only its high efficiency (linked to graphene’s light weight) but also its very high thermal coefficient, which lets it disperse heat rapidly from the speaker coil within the tight confines of a compact consumer product. Gaskell claims that Ora’s graphene cone weighs only one-third as much as a comparable mylar one, which translates into an increase in battery life of up to 70 percent.
Ora is not the only organization investigating graphene’s potential in audio. As Spectrum has reported, researchers at the Korea Advanced Institute of Science and Technology and the University of Exeter in the UK have recently announced breakthroughs in the use of graphene to produce speakers that have features unavailable with conventional units. The audio speaker, little changed since its invention in the Victorian era, seems poised at last for a major upgrade.
Glenn Zorpette is editorial director for content development at IEEE Spectrum. A Fellow of the IEEE, he holds a bachelor's degree in electrical engineering from Brown University.