Just for accuracies sake ... there *are* actually eight speakers in the car. The top position in each door has a tweeter mounted in front of a midrange.
As well, the rear speakers are dual voice coil 6x9s - allows more power from the HK amp without needing very high output voltages. So the HK amp has *ten* outputs, to *eight* speakers, in *six* positions.
No wonder people get confused!