Originally Posted by
davef
Please don't take this the wrong way, but how many creased soft dome tweeters have you examined? In a tweeter like this one, where the dome is very soft and heat treated to retain the shape - you are not going to get that typical hard crease line like you will see with more common Asian made domes. These domes are sealed - meaning there is a very specific amount of air-pressure beneath the dome that stays the same.
2 things will happen when the dome pushes in -- there will be an inward crease at the point of contact with the dome, and then there will be an outward crease as the additional air-pressure created by the depression pushes the dome outward. You can clearly see this on the attached pic I just took for you of my finger pushing in the dome on the same tweeter.
Because these domes are so soft, they typically won't ever leave that telltale hard inward crease line you mention, but - if the pressure against the dome causing the depression is sustained for a while - the dome itself will slightly deform around that outward bulge and you end up seeing exactly what you have documented here.