Can't say I've had the same problem but I do have the Auditorium 200 in my car. I presume you've reset the balance and fader defaults? Next thing would be to check the rear connections - the InfoCentre just pops out - use a screwdriver and some padding to avoid damage to the leather.
You might also want to check the connections to the amplifier - this is a bit fiddly as it's mounted behind the battery in the boot.

You might also want to check the connections to the amplifier - this is a bit fiddly as it's mounted behind the battery in the boot.