By way of clar at M5POST.com - Full DIY @ http://f10.m5post.com/forums/showthread.php?t=680384
Here are audio clips of the F10 M5 with and without its Active Sound feature enabled. The Active Sound feature reproduces the car's engine sound via the in-car audio system. In other word, if you're sitting inside the car you not only hear the engine coming from outside, but also an audio track of the engine based on throttle input, speed, and engine revs.
Full details and full DIY are at http://f10.m5post.com/forums/showthread.php?t=680384
