Automakers shush cars with noise cancellation technology
— -- When it comes to creating quieter cars, automakers are giving a whole new meaning to the sounds of silence.
More of them are using technology to mask bad sounds and enhance good ones. Engineers say manipulating sounds in a car adds to perception of quality and harmony.
"Our aim isn't to trick the customer," says Chuck Gray, chief powertrain engineer on Ford's electric vehicles. "It's to give them the best experience."
When it comes to eliminating unwelcome sounds, the new technology works like noise-canceling headphones. A few automakers have used the strategy in luxury cars, and it's now starting to filter down into mainstream models.
"Active noise cancellation works to get rid of noises that customers don't want to hear," says Honda spokesman Chris Martin.
The new 2013 Honda Accord, where the goal is to make the cabin as quiet as possible, employs microphones pick up engine, wind or road noise. A computer then produces almost indistinguishable sounds, projected back into the cabin through four speakers, in frequencies that reduce or cancel out the unwanted sounds.
At the same time, automakers are also taking steps to enhance the good sounds. In performance cars, they are literally piping sounds from deep within the engine, like in the new BMW M5 and M6. Some automakers allow drivers to tune the sound to their preference. The 2012 Porsche 911 sports car, for instance, has a button that opens up the exhaust sound, from purring kitten to snarling beast.
But mostly, the emphasis is on quiet. Infiniti's technology in its M sedans, which also involves four microphones in the cabin, is from Bose, a leading maker of noise-canceling headphones.
Ford has added noise cancellation to a couple of its Lincoln luxury cars, the MKS large sedan and the redesigned 2013 MKZ sedan. But Ford also is adding it on some lower-cost, high-mileage models â?? the C-Max small hybrid crossover and Fusion sedans, both the hybrid and plug-in hybrid versions.
Why these models? Because while their engines are tuned in the way to save the most gas, the lugging sounds they make may be unpleasant or harsh. Noise cancellation technology gets rid of the low-frequency noise.
Even engineers are surprised by how effective it can be. When it was switched on during tests, "You have a 'wow,'" says Ming-Ran Lee, a Ford noise and vibration engineer.
