The human ear is pretty impressive and hard to artificially replicate. By comparison hearing aids are still sizeable, uncomfortable and have yet to get to the point where it makes it possible to hear rich sounds that humans take for granted. Still, inserts, like crickets, may provide insight into how we can learn to to design a small speaker that is loud, just as you’d need for a hearing aid and help treat conditions like single sided deafness and unilateral hearing loss.
Crickets make sound by rubbing their wings together. The wings are corrugated in patterns which make them stiff. This makes them very loud when the insect rubs them together. Scientists can use laser vibration systems and advanced computer modeling simulations to mimic this idea, by engineering the stiffness of the speaker surface. This produces a simple and efficient way to make ultra small speakers that produce sound that is very loud.
Hearing aids are designed to operate in stages. Audio signals are collected by a microphone and then amplified to be louded. Background noise is filtered out with digital processing technology. As a result the speaker in a hearing aid can deliver high-intensity sound to an ear. Better understanding insects may help us in each of these processes.
We can learn more about bio-acoustics through the locust. It has two large “tympanal” membranes that is uses to hear. These membranes, on its chest, vibrate with sound. They transfer the audio signals to the insect’s nervous system, just like a human’s ear drum. Scientists have discovered that this membrane has a regular variation in thickness. When sound is played to it, i produced tsunami-like vibration with the peak of the wave directly at the location of the nerve cells. This allows for huge amplifications of the sound. Scientists may be able to similarly design microphones with inbuilt passive amplification based on this insect discovery.
Microphone design might also benefit from mosquitoes and fruit flies. They have tiny antennae which are tiny yet highly sensitive to sound. This could help scientists and engineers improve microphone design in devices that use them like hearing aids.
Learn more about this development at SingularityHub.