Hello Alleung,
If you are talking about little light brown spots on the ceramic mid drivers don't worry about it. This happens over time of normal use of the speakers and does not have any negative effect on the sound. Enjoy!
Tom
If you are talking about little light brown spots on the ceramic mid drivers don't worry about it. This happens over time of normal use of the speakers and does not have any negative effect on the sound. Enjoy!
Tom