Make sure there is no one else in the room and gently suck on it. I know that this sounds ridiculous and I am leaving myself wide-open for major A'gon teasing, but it really worked for me on my old Dynaudios.
Dimple in speaker driver cone
I have a pair of Thiel CS 1.6s that have a quarter size dimple in one the driver cones of one speaker that a friends curious child created when he pushed his finger into my speaker (damn him). Can that dimple be removed by moi? Or do I need to have it repaired or replaced by the manufacturer?