A sound investment: optimising graphene for loudspeakers
Lightweight, strong and inexpensive – a new graphene-based material has the potential to enhance both the performance and battery life of loudspeakers. Charlotte Ashley finds out more from inventor Robert-Eric Gaskell.
“I started playing violin when I was four years old and played in bands throughout high school, but always found myself more interested in taking apart and rebuilding the amplifiers that we used than playing music itself,” says Robert-Eric Gaskell. He would go on to co-invent a graphene oxide-based composite material that has the potential to improve sound quality in a variety of environments.
The material was born from a conversation with his brother, an electronic engineering specialist, during their time studying at McGill University, a public research establishment based in Montreal, Canada. “The project was really a cross-pollination between my department (sound recording) and my brother’s. One day we were discussing the mechanical properties of graphene and I realised it had significant potential for use in transducers.” He adds: “I was very interested in the sound quality and the improvement that it could bring in terms of its stiffness and avoiding distortion.”
What started as a side project turned into something much bigger for Gaskell, who would go on to create the laminate material dubbed ‘grapheneQ’ (named after its low Q resonance) with his brother Peter and guidance from Canada’s research chair in Nanoscale Electronics Dr. Thomas Szkopek. When funds from an innovation grant from the university’s engineering department ran out, another opportunity arrived. “We got some attention from a technology incubator in Montreal called TandemLaunch, who saw our patent application and was interested in the possibility of commercialising the technology.” The CAD $500,000 (€355,000) start-up funding from TandemLaunch helped Gaskell to co-found materials company Ora Sound - where he works as audio technology lead - and move on from other career options in the US (including building ribbon microphones and even being a musician in a popular rock band).
“By remaining very strong and stiff, it [grapheneQ] avoids negative distortions.”
Graphene, the thinnest known material, has become somewhat of a hot commodity recently, although not yet fully commercialised since the first graphene speaker was assembled because of the high cost of manufacturing large areas of the material. Its core qualities - being extremely light and strong (25 times stronger than steel) - meant it ticks two key boxes for transducer designers, something Gaskell was keen to capitalise on. “Stiffness can improve sound quality because it reduces the amount of speaker breakup, whereby the membrane stops moving pistonically, and you get sympathetic vibrations which were not intended in the original source,” says Gaskell. “By remaining very strong and stiff (Young’s Modulus of up to 130 GPa), it can avoid those negative distortions.”
The lightweight quality of grapheneQ also means the company is able to improve the efficiency of drivers. “Around the time we were working on this it became clear that the trend in audio was for wireless, therefore having such a lightweight material would offer distinct advantages when it came to loudspeaker efficiency, which would translate in to better battery life for portable electronic devices.” Operating just a few nano-amps means grapheneQ in theory can provide up to a 50% increase in battery life compared to current speakers. The material additionally can minimise speaker damage from overheating thanks to high levels of thermal conductivity.
As many in the industry have backed graphene taking off, the company is also able to benefit from manufacturing costs of grapheneQ being reasonable, with membranes costing as little as US $0.02. Gaskell adds: “A lot of our estimates are based on the small quantities that we currently purchase so we’re hoping that once we ramp up production and buy in larger quantities, that the cost can be even more reasonable.”
Ora Sound had its first outing earlier this month at CES (Consumer Electronics Show) 2017, introducing headphones incorporating grapheneQ diaphragms, but getting to this point has not been without its challenges. “Our biggest difficulty has been learning how to directly form the material into the appropriate shapes for loudspeakers, like the cones and domes for woofers and tweeters,” says Gaskell. “The material doesn’t immediately lend itself to being shaped in to these different forms.” Manufacturing the material has also been a learning process for the five-person team at Ora Sound; “Initially it took us about a week to form a single membrane and we’ve managed to get that down to a few minutes.”
During the early stages of the project - faced with the prospect of cold calling engineers – Gaskell admits he had his doubts but says the response they’ve had has been fantastic.” He continues: “We are being contacted from companies all over the world that are interested in being able to improve their loudspeaker performance.” The majority of this interest currently comes from loudspeaker manufacturing hubs such as the US or China, as well as Germany and Denmark.
The next stage in Ora Sound’s route to market is raising series A funding and hiring a CEO within the first half of 2017. It will also continue to form development agreements with major loudspeaker manufacturers who will test the material in different applications and provide feedback to optimise the material. The company’s main ambition is to eventually have its own contract manufacturer for the material who will produce cones and domes to the company’s specifications, and sell to OEMS. Gaskell and the rest of the Ora Sound research team are confident grapheneQ will become a standard for loudspeaker membranes in the future; “I think that in that in the next five years it wouldn’t be surprising to see the material used in all sorts of different loudspeakers applications given the improvements it offers.”