Ultrasonic Mic Breakthrough Made From Graphene

Just like loudspeakers, basic microphone technology hasn't changed much in a hundred years or so. We have our dynamic, ribbon and condenser types, with the occasional exotic laser or flame modulation technology thrown in every so often.

Researchers at Serbia-based Dirigent Acoustics along with the University of Belgrade haven't changed the technology in the way a condenser microphone captures sound, but they have changed the diaphragm material to graphene, and with great results.

Not only has the team created the world's smallest condenser microphone, but one that's strong and flexible with a frequency response up to 1MHz.

The diaphragm used is just 25 nanometers thin (most condenser mics are around 2 microns, or 2000 nanometers) and was originally housed in a standard B&K capsule that replaced the standard capsule using a typical nickel-based diaphragm.

This could provide a quantum leap in a microphone's ability to capture sounds with more realistic results thanks to vastly increased transient response. Can a graphene based loudspeaker be far behind?

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Can This Be The Speaker Breakthrough We've Been Waiting For?

Loudspeaker technology hasn't changed all that much since Alexander Graham Bell invented the first speaker in 1876. Sure it's evolved to become much more efficient with a flatter and wider frequency response, but we're still talking about the same coil of wire mounted to a diaphragm that moves through a magnetic field that was used 138 years ago. Electrostatic loudspeakers were introduced in 1959 and while they remain the darling of audiophile set, can't take the beating of professional use and have an inherent low frequency response problem.

But that all could change thanks to a new breakthrough by two researchers from the University of California Berkley. The pair have made what is essentially a solid state loudspeaker using the ultra light and thin substance graphene sandwiched between two silicon electrodes to produce a transducer that has a fairly flat 20Hz to 20kHz frequency response.

One of the difficulties for loudspeaker engineers is that speaker design revolves around damping the various resonances in order for the speaker to have a flat response. This usually makes it less efficient and limits the response to a somewhat narrow frequency band. With a graphene speaker, there are fewer resonances to begin with, and what there is can be electronically controlled rather than mechanically, as is needed with electro-mechanical speakers today.

The new transducer is small and can only be used in ear pieces at the moment, but the technology is advanced enough that it can be applied to headphones in the near future. We might not see our concert halls, clubs and studios filled with graphene speakers in the year, but we could have them in our ears before you know it.

You can find the paper here, if you'd like to read more. Thanks to reader Paris in Greece for the heads up.