Found it, thanks guys. LOLZ.
SIB 84 05 10
Telephone (TCU): Landline Audio Quality
F07, F10 (5 Series) with option 639 (BMW Assist with Bluetooth) and without option 6VC (Combox controller)
During phone conversations using the vehicle's hands-free Bluetooth system, the person on the other end may complain that at times they cannot understand the person calling from the vehicle. Typically, this happens at speeds greater than 50 mph where there is significantly greater background noise (engine, road, wind, etc.) .
Vehicle microphone for the hands-free system.
Do not replace parts at this time. Please advise your customer that this is a known problem that will be corrected with an improved microphone, expected to be available in January 2011.
This Service Information will be updated as soon as the updated microphones are available.
This situation only affects vehicles that do not have the option 6VC (Combox controller).
Sophisto Grau / Oyster - Black Nappa, Anthracite Wood
ZAV, ZCV, ZCW, ZDA, ZDH, ZPP, ZP2, ZSP
Mods - M5 Grilles, BMWPedals Black Anodized
Heaven is where the police are British, the cooks are French, the cars are German, the lovers are Italian and it is all organised by the Swiss.
Hell is where the police are German, the cooks are English, the cars are French, the lovers are Swiss, and it is all organised by the Italians