S4Tokyo

A little more detail than Audi site provides:

http://www.bang-olufsen.com/sound-sy...udi-a4-s4-limo


select text:

'.........
Sonic intelligence

The Bang & Olufsen Sound System uses a microphone integrated in the ceiling of the cockpit to measure changing noise conditions, and automatically adapts the volume and timbral balance accordingly. At the same time, the intelligent loudness system ensures that the perceived balance of bass, mid-range and treble remains constant at all volume levels to ensure clean, crisp and precise sound at any volume and any speed as well as the ultimate convenience for the driver and passengers.
..."

Zed 2.0

This is the "GALA" setting in sound configuration.