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Graphene, due to being incredibly lightweight and impressively durable, could be the ideal solution to the production of supremely efficient audio devices. Particularly headphones.
Follow the development of any technological device over the 20th and 21st Century and you will undoubtedly see a shift in size and efficiency.
Take Televisions as an example, massive bulky units with cathode-ray tubes have been replaced by slimmer flat screen designs. In addition to this slimming down, a massive increase in efficiency and reduced power demands have allowed screens to become larger in size than ever before.
Now, the use of graphene could usher in a similar revolution in speaker and audio systems.
The current issue with headphones, even some of the most advanced on the market, is that the electrical energy they consume is mostly lost to unwanted heat. As a stark example of this, Berkeley labs states that many inner-ear headphones lose as much as 90% of the energy they consume to heat, with only 10% converted to sound energy.
This heat loss arises from the very way speakers and similar devices work. An electrical current drives the oscillation of a mechanical diaphragm, thus reproducing sound.
The key to solving this is making this diaphragm as thin as possible. Reducing the mass of the diaphragm also provides the damping that a speaker needs — which usually also demands power — naturally via air resistance.
In order to do this, researchers have been experimenting with a host of alternative materials to adapt for use in speakers and headphones, including, rather bizarrely, wood and pig intestine!
Unsurprisingly, graphene has been highlighted as a material that could deliver increased performance in audio devices should a diaphragm be made of it.
A Candian start-up, Ora Audio Inc founded by Dr. Robert-Eric Gaskell and Ari Pinkas, is just one of the companies looking at graphene as a platform upon which to build the future of sound. Their GrapheneQ (GQ) headphones capitalize on the work of Professor SonBinh Nguyen, Northwestern University, who developed a method to make graphene sheets in a scalable way, delivering remarkable quality.
Whilst the engineering skill that has gone into the lightweight design of the GQ headphones isn’t to be downplayed, it is the material qualities of graphene that deliver their impressive performance.
Without a doubt, the most exciting aspect about the technology is the unique mechanical properties it holds. It is very uncommon for such a rigid material to be so lightweight. This rare combination of high stiffness and low density allows for some pretty cool things in the audio world.
Ari Pinkas, Ora Audio Inc
Graphene and Audio Technology
Graphene is a conductor of electricity, making it perfect for use as a mechanical resonator. Qin Zhou and A. Zettl, Materials Sciences Division, Lawrence Berkeley National Laboratory, California, point out that a miniaturized graphene-based electrostatic loudspeaker also provides an excellent frequency response across the entire region for the human ear. A performance matching or surpassing most commercially available audio earphones.
To put this into context, returning to Berkeley Labs’ calculations, they say that a graphene-based headphone could use as much as 99% of the energy it consumes to convert into sound energy.
“The vast majority of our efforts went on the development of our material science technology and making sure its implementation generated the levels of sound realism that is expected from graphene’s ‘Superman-like’ properties,” Pinka explains. Ora’s unique design sees flakes of graphene placed in thousands of layers bonded with agents that cross-link it rather than simply just layer atom-thick slices.
Pinka also knows that his company, being a start-up, must play to its own strengths — just as their devices play to that of graphene — if they are going to compete with the ‘big boys’ of the audio industry.
We are basically a bunch of chemists, materials scientists, audio engineers…there’s not many marketers at Ora. The plan at the moment is to focus our efforts on including our patented graphene materials inside the next generation of consumer devices — we’re already working closely with major brands paying us to develop solutions for their headphones, hi-fi tweeters, TVs, smart speakers, laptops and even smartphones.
Ari Pinkas, Ora Audio Inc
Sources and Further Reading
Mraz. S. J, [2020], ‘Graphene Membrane Could Revolutionize Speakers,’ Machine Design, https://www.machinedesign.com/mechanical-motion-systems/article/21126777/graphene-membrane-could-revolutionize-speakers
Zhou. Q, Zettl. A, [2013], ‘Electrostatic Graphene Loudspeaker,’ Zettl Group.
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