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There are many sources of debate on a long road trip, including route selection, the choice of snacks, and, probably most importantly, what to play on the radio. Finding a way for all parties to listen to their own audio without the need for headphones has been a goal of car makers for decades and scientists may have finally managed it.
A team from the University of Le Mans in France carefully positioned microphones, speakers and filters（过滤器）to create personalised sound zones(PSZs) inside a car, and the small regions are where sound from a set of speakers can be heard clearly. Outside these, it cannot be heard.
One barrier which scientists have previously been unable to overcome was the impact of moving one's seat. They were able to form a PS2, but unable to move it to follow a person if they moved the seat forwards or backwards.
The French team created a new algorithm（算法）specifically to tackle this issue, which handles the sound waves to create "bright" and "dark" zones in the car. "Loudspeakers are placed in the headrests. and specific filters for each transducer（换能器）are calculated to reproduce a sound signal that maintains good quality in the zone under consideration and is strongly weakened in other zones. " said. Dr Lucas Vindrola, the author of the study. "The key to the technique working properly is having sufficient microphones placed around the car to detect how many people are in the car and where they are sitting. The price to pay is to have control microphones in the passenger section, so that the algorithm can work. "
However, the technique is not yet ready to be commercially rolled out as a luxurious optional extra just yet, as it currently works only for a limited range of frequencies.
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