Nano-materials start-up uses graphene to sweeten loudspeaker response

The company believes that graphene holds the ideal properties sought after in loudspeaker diaphragms: stiffness (graphene is stronger than diamond) and lightness (graphene is the thinnest known material, one atom thick).

Building acoustic transducers with these properties allows for the production of smaller, lighter, more energy-efficient loudspeakers, while also improving sound quality. However, the difficulty and expense of mass-producing graphene has presented a roadblock to bringing the material to consumer products.

“Pristine graphene has incredible mechanical properties but by current manufacturing techniques, it is cost prohibitive,” said Dr Robert-Eric Gaskell of McGill University, co-founder of Ora. “It’s difficult to deposit and to shape.”

While some consumer products have begun mixing small amounts of graphene (perhaps 5 per cent) into polymers for added strength, such low percentages of graphene are not sufficient to get significant performance improvements in loudspeakers.

Ora has now revealed a new technology that consists almost entirely of graphene, obtaining impressive strength at a very low weight that can be formed through a simple industrial process directly into the cone and dome shapes used in loudspeakers.

“It’s the world’s first dynamic loudspeaker made from graphene. It’s important because the vast majority of loudspeakers are dynamic,” said Xavier Cauchy, Ora’s co-founder and materials scientist. “There are a handful of research groups working to bring the exciting properties of graphene to the audio industry. There has been some fascinating work on initiatives such as thermoacoustic and electrostatic speakers. What makes Ora different is that our approach is compatible with current technology.”

Ora’s patented technology can be made using as much as 98 per cent graphene by weight. Flakes of graphene bonded together with oxygen and other proprietary additives form a laminate material that Ora has named ‘GrapheneQ’.

“We are calling our material ‘GrapheneQ’. It’s low-density, high-stiffness allows for drivers with a lower Q resonance, requiring less damping and improving sensitivity,” said Dr Gaskell.

Today, most loudspeakers use either paper or Mylar diaphragms, with a multitude of other materials also sometimes used. The characteristics of the diaphragm material will affect the performance of a speaker, influencing the power efficiency, frequency response, distortion and required damping. Manufacturers will occasionally opt for very expensive, esoteric materials such as diamond or Beryllium to make high-end products with a price tag to match. Graphene offers an elegantly simple solution with an ideal balance of strength, density and damping.

“We set out with the goal of improving sound quality by bringing graphene to the audio industry. We ended up with an approach that not only improves sound quality but is also simple, economical and works as a drop-in replacement with most current loudspeakers. It is likely that graphene could be in many consumer audio products in the not-too-distant future,” said Cauchy.

The reported stiffness of Ora’s ‘GrapheneQ’ (Young’s Modulus of up to 130 GPa) in speaker membranes could potentially allow for the development of ultra high-fidelity audio products at a fraction of the price that they cost to build today.

Additionally, because the material is exceptionally lightweight, requiring less power to move it, replacing an existing speaker diaphragm with one of ‘GrapheneQ’ could double the efficiency of a speaker, considerably extending the battery life of portable audio devices – crucial at a time when the audio industry is moving towards entirely wireless products.

Over the next few months, the Ora team will be showing potential partners, customers and investors how ‘GrapheneQ’ could become a standard material in the production of loudspeaker membranes. Graphene may be a revolution for dynamic loudspeakers, a technology that has seen little innovation since its invention in 1921.

Since it’s introduction on the world stage – when its discovery won the 2010 Nobel Prize in Physics – graphene has been touted as a wonder material, suitable for myriad uses. Commercial products predominantly based around the use of graphene, and actively exploiting the material’s unique properties, are now beginning to emerge. For example, an Italian luxury design firm recently presented its graphene-coated motorcycle helmet that dissipates internal heat and is less prone to cracking in a crash. 

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