Cadillac ELR takes active noise cancelling to the limit

2014 Cadillac ELR The all-new 2014 Cadillac ELR’s interior is so quiet when running on battery power that theelectrified luxury coupe’s development team took care to keep it that way when the on-board gas-powered electric generator turns on for extended-range driving.
ELR uses active noise cancelling to uniquely preserve the peace and quiet. While most cars that use this type of sound-neutralizing technology aim simply to mute exhaust boom at low engine speeds, such as when idling, ELR uses it across all engine speeds.
“Acoustic refinement is an important attribute of every Cadillac interior, and ELR is no exception,” said Chris Thomason, ELR vehicle chief engineer. “Considering how quiet the car is during pure-electric driving we knew the generator sound had to be as pleasant as possible, and we were able to achieve it with active noise cancelling.”
The active noise cancelling system in the ELR electronically gathers input from the vehicle’s generator and powertrain, as well as from three ceiling-mounted microphones. The system calculates and produces the appropriate noise-cancelling signal, which is delivered through the Bose® audio system’s speakers and subwoofer.
ELR’s engine functions primarily as a range-extending, gas-powered generator for its advanced electric drive propulsion system. Active noise cancelling keeps the ELR’s interior quiet during extended-range operation, including long-distance drives and steep ascents.
Active noise cancellation also helped eliminate the need for additional sound-deadening materials, reducing mass, which saves energy and helps deliver spirited performance.  ELR uses a variety of sound-buffering and -absorbing materials to minimize wind, road and engine noise, including:
Acoustically laminated windshield and thicker front-door glass
Liquid-applied sound deadener applied to the floor pan, trunk and roof
Triple-sealed doors with acoustic perimeter water deflectors
Mass-efficient sound-absorbing dash mat and carpet system
Acoustic foam baffles inside body cavities and in between inner and outer quarter panels
An isolated front suspension cradle with hydraulic powertrain mounts to isolate road and engine vibration
ELR is available nationwide in the U.S. beginning in January 2014.
Source: GM