Active Cabin Noise Suppression

Basic Description

Most vehicles with an internal combustion engine utilize materials and passenger compartment designs intended to isolate the vehicle occupants from engine and road noise. A few vehicles employ systems that actively generate an "anti-noise" signal inside the cabin using one or more strategically placed speakers driven by a microprocessor. These systems monitor the noise inside the vehicle using microphones and attempt to cancel the noise by generating a similar signal that is out-of-phase with the detected signal.

The principle is similar to that used by noise-canceling headphones only the volume in which the noise must be cancelled is much larger. This makes it very difficult to cancel the noise uniformly throughout the cabin at frequencies above a few hundred hertz.

Systems available today are typically capable of reducing steady state noise (e.g. road and engine noise) at frequencies up to a few hundred hertz by 5 to 10 dB.

Sensors

Microphones

Actuators

Speakers

Data Communications

Typically none required.

Manufacturers

Bose

For More Information

[1] Active Noise Control, Wikipedia.

[2] Toyota to Fit Active Noise Canceling to Crown Hybrid, The Motor Report, July 18, 2008.

[3] Active Sound Control in 2010 Acura RL, Acura web site.