Podcast: Is Your Car a Good Listener?

Electric cars are in general much quieter than those that run on combustion engine. The car's fan noise is much softer, compared to a typical combustion engine's gasoline-guzzling growls. 

You might think acoustic engineering is less critical in the quieter electric cars, but experts point out, it's the opposite. When the car is much quieter, the driver and passengers begin to notice other sounds, such as wind noise and window rattling. 

On the other hand, the car cannot be completely silent. It has to produce a required level of sound (required by law in many regions) so pedestrians can hear it approaching and get out of the way, if needed. 

In self-driving cars, in addition to seeing traffic signals and obstacles, the autonomous car must also listen to its surrounding for sounds like emergency vehicle sirens, then take appropriate action. So the car needs to be a good listener, to make up for the driver who may only be partially engaged.

Striking a good balance involves careful placement of microphones and speakers, and modeling the audio environment of the vehicle in simulation software. Here, the car's geometry plays a key role. The shape of the car determines the airflow around it, and consequently the wind noise it generates. It also determines the enclosed space within which sounds propogate. 

The simulation physics get much more complicated as you pile sound propagation on top of the speakers' electromagnetics and wind friction.

In this podcast, part of our latest feature titled "Is Your Car a Good Listener?" (August/September 2020 issue), Ales Alajbegovic, Vice President of World Wide Industry Process, SIMULIA, Dassault Systemes; Siva Senthooran, Director of Technical Sales, SIMULIA, Dassault Systemes; and Mads Jensen, Technical Product Manager for Acoustics, COMSOL, discuss what it takes to teach a car to listen; and how to listen to the car before it's built.