Autovolt Magazine

You Can Hear a Pin Drop inside Cadillac’s ELR EV

To be fair, we’ve not put that to the test, but Cadillac claims it’s new ELR interior is so quiet, especially when running on just battery power, that the coupé’s development team took great care to keep it that way when the on-board petrol powered generator turns on for extended range.

How did they do that? The ELR uses active noise cancelling to preserve the peace and quiet. While most cars using 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 speeds.

“Acoustic refinement is an important attribute of every Cadillac interior, and ELR is no exception. 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.”

Said Chris Thomason, ELR vehicle chief engineer.

More commonly associated with mobile telephones and high end headphones which often feature active noise cancelling by having a dedicated microphone recording surrounding noise. Opposite wavelengths are then processed effectively cancelling out the unwanted exterior noises altogether.

Using the same techniques, the active noise cancelling system in the ELR electronically gathers input from the vehicle’s generator and drivetrain, as well as from three ceiling-mounted microphones. The system then calculates and produces the appropriate noise-cancelling signal, which is delivered through the Bose® audio system’s speakers and subwoofer to the cabin occupants.

2014 Cadillac ELR - Active Noise Cancelling

ELR’s engine functions primarily as a range-extending, petrol-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

Source; Cadillac