Skip to main content

Graphene speaker produces sound with good (non)-vibrations

graphene speaker heating cooling 20170502 151509
Image used with permission by copyright holder
Sound is the result of a pressure wave in the air. A regular speaker creates this wave by physically moving back and forth, regardless of whether it’s a magnetic coil-driven speaker or a membrane-based one. Thermo-acoustic sound generation is different. It causes the necessary pressure wave not by physically moving a component, but by periodically varying the temperature of the air next to it.

To achieve this, a material is required that’s able to heat up and cool down very rapidly, at a rate comparable to the frequency of the generated sound. That rules out a lot of metals because, although they conduct heat quickly, they turn out to be too good at storing heat over a long period of time.

The answer? According to a new piece of research coming out of the U.K.’s University of Exeter, it could be to use all-around wonder material graphene to create a non-moving solid-state audio device that may one day replace your existing bulk sound system.

“Graphene is great at conducting heat but, as it is just a single sheet of atoms, it has really poor capacity to store heat,” Dr. David Horsell, a professor of physics who worked on the project, told Digital Trends. “As a result, it can heat and cool at a very high rate indeed – enough to generate sound at audible frequencies and at much higher, ultrasonic frequencies.”

There are several possible applications for the work of Horsell and his colleagues, which go beyond merely acting as a replacement for regular hi-fi systems. One is to incorporate the tech into ultra-thin touchscreen technologies, which would no longer need separate speakers as a result, since the screen could be made to produce sound on its own — courtesy of a thin, invisible layer of graphene.

Another possible use-case concerns ultrasonic imaging or treatments in healthcare, since being small and potentially able to be produced on flexible substrates could allow a host of new medical techniques to be realized down to very small scales.

“There are two key aspects of the work we want to explore next,” Horsell continued. “The first is an issue with efficiency: Can we increase it enough to make graphene-based speakers compete with current, established loudspeaker technologies? For this, we need to look at exactly how the power we put into the graphene is dissipated. The other aspect we had not expected is that if you ‘listen’ closely to the graphene, it can start to reveal secrets of its inner workings. We have already seen that small nonlinearities in the conduction in graphene [are] translated into a specific frequency of sound output. We want to explore this further to see what other details we can discover just by listening to graphene when we question it with different electrical signals.”

An article describing how the researchers were able to combine speaker, amplifier, and graphic equalizer into a chip the size of a human thumbnail was published in the journal Scientific Reports.

Editors' Recommendations

Luke Dormehl
I'm a UK-based tech writer covering Cool Tech at Digital Trends. I've also written for Fast Company, Wired, the Guardian…
Ikea’s new Symfonisk Table Lamp speaker lets you mix and match lampshades
Ikea Symfonisk Table Lamp Speaker (gen 2).

Ikea has a new version of its Symonisk Table Lamp speaker and, as rumored, it now comes with a choice of lampshades, something the first-generation Table Lamp lacked. The new model, a continuation of Ikea's collaboration with wireless home speaker maker Sonos, will be sold in components. The base, containing the speaker and the light socket, will be available in black or white for $140. You can then top this base in a $29 fabric-based lampshade in black or white, or a $39 glass lampshade, again in black or white. The new model will be available at Ikea's U.S. stores and online at beginning October 12.

The ability to mix and match lampshades is a big improvement over the original version, which forced you to choose either a white base with a matching white glass lampshade or a black base with a smoky-grey glass shade. But it's not the only change: Ikea has also swapped out the small, candelabra-type E11 light socket for the much more common E26/E27 base, which most folks will recognize as a standard Edison light bulb. This gives the new Table Lamp the ability to work with many more kinds of light bulbs, including Ikea's own line of Tradfri Smart LED bulbs.

Read more
Sonos is raising the prices of most of its speakers
Person carrying the Sonos Roam 4 on the beach.

Sonos is increasing the price of its wireless speakers starting September 12. The new prices will affect popular models like the Sonos One, Sonos One SL, and the company's most recent addition, the Sonos Roam portable speaker.

While some of the increases aren't dramatic percentage-wise -- the Roam is only going up by just under 6% -- it's still somewhat shocking to see a product like the Sonos Arc, regularly $799, go up by $100 to $899. The full list of price increases can be seen below.

Read more
Bowers & Wilkins’ pricey flagship speakers get an expensive update
Bowers & Wilkins 801 Series Diamond D4.

If you're a fan of the kind of pristine audio quality that only the best loudspeakers can provide, get ready to liquidate some savings. Bowers & Wilkins (B&W) has just released its first update to its flagship 800 Series Diamond speakers since 2015. Along with a new internal design, new materials, and an intriguing new driver suspension invention comes a much loftier set of prices. The range-topping 801 D4 commands $35,000 per pair, a $5,000 (or about 17%) increase over the British audio company's current top model, the 800 D3. Similar increases apply to the entire new lineup of seven models, which will be available from B&W retailers starting September 1.

From left: Bower & Wilkins' 801 D4, 802 D4, 803 D4, 804 D4, 805 D4, HTM81 D4, HTM82 D4 Bowers & Wilkins

Read more