Pioneering science developed a completely new and better method. It’s based on principles of ultrasound that create sound only in the targeted areas and silence elsewhere. We pair ultrasound with the principles of nonlinear acoustics. As each pair of beams cross, they produce an entirely different sound wave, which due to interference, is only detectable at certain points across the human hearing range. This advancement has the potential to revolutionize sound creation and manipulation in arts and sciences alike.
Understanding Ultrasound and Human Hearing
Ultrasound is made up of all sound waves above 20 kHz, which are ultrasonic or beyond the range of human hearing. Humans can only hear sounds that are below this threshold. This quality makes cosmetic ultrasound ideal for covert communication and many other applications.
The new technique uses two ultrasound waves of slightly different frequencies—40 kHz and 39.5 kHz. On their own, these frequencies are inaudible to human ears. When these two beams cross, they create a second sound wave at the beat between their frequencies.
The Mechanics of Frequency Difference
The frequencies of the two ultrasound beams differ. You heard it right — this difference produces what is often a very loud sound wave at 0.5 kHz, or 500 Hz. This frequency falls within the human hearing range. It converts an ultrasound signal that was once almost undetectable into a sound that we can actually hear in the right circumstances.
This method offers an innovative solution to a longstanding challenge in acoustics: controlling where sound travels. By default, sound waves diffract, meaning they naturally expand as they travel through a given physical environment. Because of this spreading, it is very tricky to aim sound targeted more precisely without spilling over into unwanted spaces.
Overcoming Diffraction with Ultrasonic Beams
The new technique uses ultrasonic beams that can bend on their own. This novel property enables scientists and engineers to focus sound waves with extreme precision to target locations. This innovative technology essentially cancels out impacts by producing sound waves of equal energy and opposite phase at the targeted points. It holds promise to transform things like targeted audio communication and enhanced sonar systems.
The capacity to manipulate sound with such accuracy ushers in a new age of possibilities for commercial and scientific pursuits. Whether increasing privacy in public spaces or creating advanced audio detection technologies, the consequences are enormous.
Future Applications and Possibilities
The impact of this study reaches far into various sectors. In one example in healthcare, industrial-grade targeted ultrasound could make diagnostic procedures more efficient by delivering sound waves exactly where you want them. In consumer electronics, it could result in more sophisticated audio systems that can provide a tailored sound experience.
When applied to security and surveillance, the potential benefits from this technology become enormous. This might enable more sensitive and discreet communication channels and in-the-moment alert systems that light up only under certain conditions. The applications for this innovative material are limitless, and further research will surely discover other promising applications.
