You have now baffled me too as I have just gone and checked again, there is no air or vibration coming out of the middle front dashboard speaker which seems to sugget it is only a dummy as the other speakers on the side door are producing air and vibration out of them which leads me to believe they are in use. Maybe as someone else has suggested you just got lucky and been given the hifi speaker system added as a mistake. But I am 95% sure it is only 6 speakers due to no sound or air or vibration coming out of the middle dashboard speaker as if it was hifi it would have showed some signs which it aint.