Here’s the latest form of tying the radio to car functions. The 2012 BMW M5 car radio mimics the sound of the car’s engine revving and whining as you drive.
BMW apparently had to keep the engine noise (external) to legal guidelines but didn’t want drivers to miss the sweet roar of acceleration. So it tied the DSP of the sound system directly to the engine management system, “allowing it to reflect the engine’s revs and torque, and the car’s speed over the road,” said page 34 of a 47 page press release for the car that will formally debut in a few months at the Frankfurt Auto Show.
BMW calls this “Active Sound Design” technology and it was specially developed for the new M5.
The fake engine noise seems to be in real time because the system “takes its cues from the firing sequence of the eight-cylinder engine and the frequency range of the exhaust system. This gives the driver an extremely accurate impression of current engine load and an even more intense sensation of the V8’s high-performance characteristics,” said BMW.
When you switch the car into “Sport” mode, the simulated engine noise intensifies.
CNET notes this audio feature is the polar opposite of the noise cancellation technology in the Honda Odyssey minivan, which uses the car audio system to cancel out cabin noise through out-of-phase sound waves. Also the Prius uses external speakers so the quiet engine doesn’t go unnoticed by pedestrians.
BMW did not respond to a request for more information.
Above is a video of a rare public test drive of the car, where you can hear the engine simulation when the car goes up to 180 miles. The F10 Forum says it sounds like a jet.