Sounds like teen spirit.

Assume that you have a wannabe tuner car. A four-cylinder engine. You've added a pipe for cold-air induction. But it's still a four-banger. It could sound a whole lot more aggressive. Siemens VDO Automotive (Auburn Hills, MI) has taken some technology that has developed while doing work on powertrain sound for OEMs (they're interested in getting appropriately pleasant sounds from under the hood) and have created an aftermarket product with it, that it introduced at the Special Equipment Market Association (SEMA) show in Las Vegas. Testing the waters, in a sense, with the tuner crowd. The Active Noise Control (ANC) system includes a microphone that's located in the air intake system. It monitors and measures the sound from the valves. A controller calibrates the tones. The driver gets to make a selection of four more robust sounds. And a loudspeaker that's fitted into the ANC module that's attached to the air intake makes the engine sound ENORMOUS. (It doesn't, however, make the car go any faster.)

Siemens VDO Automotive is continuing to pursue work with the OEMs for other applications of ANC (e.g., reducing engine noise by generating sound that's opposite to that which is being generated by the engine).--GSV