- Twin ultrasound transducers create highly focused audio
- Curved sound waves aren’t audible if you’re not in the sweet spot
- Could be great in classrooms, exhibitions or vehicles
Wouldn’t it be great if you could have all the benefits of headphones without having to bother with the headphones? That’s what a new technology creating “audible enclaves” could one day deliver.
The technology comes from professor of acoustics Yun Jing at Pennsylvania State University, whose team has found a way to project sound so that only the intended listener can hear it. It’s currently short range – about 1m – and relatively quiet at 60dB, but both range and volume should be improved by using higher power transmitters.
How do audio enclaves work?
Audio enclaves are made using ultrasound waves, which are higher frequency than the sound waves we can hear. Two waves are passed through acoustic lenses that bend them, creating a curved path for the waves to follow. Those paths converge at the destination – that’s you.
The clever bit here is that each individual wave is inaudible on its own, so nobody hears anything unless they’re at the sweet spot where the two waves are in the right place for the listener’s ears – then they form something your brain can actually make out.
The hope is that the technology could be used to deliver private audio in public places, such as in classrooms or at outdoor venues, and possibly inside vehicles too.
This isn’t the first time we’ve been promised personalized directional audio. In 2016, Turtle Beach announced their Hypersound speakers which used transparent glass to create “highly directional audio”. The promotional video is below.
Turtle Beach announced a partnership with Chinese audio firm Audfly in 2021, and the resulting Focusound speakers demonstrate one of the downsides of the tech: where normal speakers start at a double-digit low frequency (ie, down to 20Hz), these directional speakers have a much higher starting point: 500Hz to 600Hz. That makes them good for speech but not great for music.
This tech isn’t likely to remove all need for the best wireless headphones, and may not work on something like an airplane, where the ambient noise is so loud that you’ll still need some of the best noise cancelling headphones – but imagine if you could switch your TV to sending sound that only you can hear with a push of a button once the family goes to be, or imagine hearing interesting commentary about a museum exhibit simply by standing in the right place. No headset needed – I like the sound of that (if I’m in the sweet spot).
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