Bose has developed a version of its QuietComfort noise-cancelling headphones for cars, which promises to minimise unwanted sound inside the vehicle.
The US audio company's new QuietComfort Road Noise Control (RNC) measures vibrations on the vehicle body caused by driving over uneven surfaces and sends a cancellation signal through the car's speakers, reducing the road noise that passengers can hear.
Bose says the system is "a smarter, more flexible and adaptable electronic solution" than previously available.
QuietComfort RNC now available to automakers
"For years, we've been asked why we can't simply adapt our noise-cancelling headphone technology to vehicle cabins for a quieter driving experience," said Bose automotive, active sound management solutions manager John Feng.
"But we know it's much more difficult to control noise in a large space like a car cabin compared to the relatively small area around your ears," he continued.
"However, through research advances and our relentless efforts to solve tough problems, we've achieved a level of road noise reduction that sets Bose apart from competitive offerings."
QuietComfort RNC is now available to automakers working with Bose, and is custom engineered to specific vehicle models during development.
Noise-cancelling technology ideal for electric cars
Its active noise-cancelling is likely to be especially relevant for electric cars, which don't have the rumbling of an internal combustion engine to mask the sound of driving over rough roads.
With some countries and companies moving to phase out petrol engines over the next few years, electric vehicles are set to become more and more common.
A combination of accelerometers, signal-processing software and microphones work to negate road noise in QuietComfort RNC.
The accelerometers, mounted on the vehicle body, continuously pick up vibrations as the car drives, while the software calculates an acoustic cancellation signal based on this data and delivers it through the vehicle's speakers.
In essence, the competing sound waves from the road and the speakers cancel each other out. Cabin microphones monitor the effectiveness of the signal and allow the system to make further optimisations.
This kind of active sound-management technology is slowly easing the car industry's reliance on conventional sound-reduction approaches, such as adding insulation to the vehicle body or making changes to the tires.
Bose points out that these measures can increase the car's overall weight and decrease its fuel efficiency.
Production models to have technology by 2021
The company will combine QuietComfort RNC with some of its existing technologies — Engine Harmonic Cancellation (EHC) and Engine Harmonic Enhancement (EHE) — to make a comprehensive sound-management system for cars.
It expects the first production models equipped with QuietComfort RNC to launch by the end of 2021.
Founded in 1964 by a Massachusetts Institute of Technology professor, Bose is best known for its speakers and headphones but has also been providing car sound systems since the early 1980s.
The company has been innovating on several fronts, recently launching Frames — a pair of sunglasses that channel audio to the wearer's ears.