Toggle switch in back of speaker?

[SocialCircle]

I just purchased a used Dynaudio Contour Center to match my Dynaudio 1.3 MKIIs. This speaker has a toggle switch on the rear. It can be set up or down or in neutral position. It says MID and has a plus and minus sign on the piece that says MID. I assume you can make the midrange more or less pronounced or neutral. But I'm not sure. Anyone know for sure what this toggle switch is for and what position I should set it in?

[Sir Terrence the Terrible]

I just purchased a used Dynaudio Contour Center to match my Dynaudio 1.3 MKIIs. This speaker has a toggle switch on the rear. It can be set up or down or in neutral position. It says MID and has a plus and minus sign on the piece that says MID. I assume you can make the midrange more or less pronounced or neutral. But I'm not sure. Anyone know for sure what this toggle switch is for and what position I should set it in?

I believe it is designed to optimize and match the image height of the center speaker to the left and right main speakers just in case their height is not equal.