Toyota has developed a noise cancelling system that could make Lexus cabins almost silent in the future. The system works using the same principle as noise-cancelling headphones. Microphones are installed in the car’s roof to detect ambient noise in the cabin. Speakers then play back an opposing frequency to effectively cancel the noise out. Toyota says its sound deadening system will be capable of muting low-speed engine hum and tyre roar. It will be used on the next generation of the Toyota Crown Hybrid, which is sold in Japan only, but the system could be used on other cars within the brand portfolio, including Lexuses.Other noise cancelling systems have been developed in the past, including ones created by Lotus and Mazda. They are likely to become more popular as manufacturers turn to them as a way to reduce the weight of sound-deadening materials in modern cars.