Amplifier
The Premium and Prestige audio systems both have external amplifiers. The amplifier in the Prestige system has a higher output power than the Premium. It is available in two models, one for the 4D and one for the 5D.
Premium has 7 output channels and Prestige 9 output channels for speakers. The two additional output channels on the Prestige system are for bass speakers in the parcel shelf on the 4D or on the right-hand side of the luggage compartment on 5D.
The amplifier has a separate power supply. It is not connected to the bus.