When you pay $100,000 for a red-hot BMW M5, you expect the twin-turbo V8 to emit a mighty song. Those who drive this superbrutal version of the midsize BMW are not generally in search of silence. And a nudge on the accelerator fills the cabin with a richly satisfying ascent from low rumble to high scream. But it’s a recording, a virtual roar.

I was stunned when I first learned in the December issue of Automobile magazine that the sound you hear inside a 2013 M5 will be coming from its speakers, and, to judge by subsequent letters and Web chatter, I am not alone. “I don’t believe it! A car that lip-synchs!” moaned one correspondent.

The sound doesn’t even come from a microphone in the engine compartment, which would make some perverse sense, but from a digital recording: “a discreet soundtrack in keeping with the harmonious and assured characteristics of the V8 power plant,” BMW explains in its literature. Stomping on the gas pedal, the Bavarians continue, “prompts an immediate audible response to match the instantaneous — and typically M — burst of power from beneath the bonnet.” They call it Active Sound Design.

I tried to put this in perspective. We all know that much of what we hear in life is not really so. Canned laughter and “sweetened” applause have been TV staples for decades, and all the slamming doors, breaking glass and squealing tires you hear in movies are sound effects. (I always notice when they have tires squealing on dirt roads.)