The hole on that page.There are adjustments to the appropriate sound. Must have the well design and calculation? In the section of the inner black wadding is prevents dirt and water into the speaker.
Hole on the tuning function properly. Must be designed and calculated well in most of the fiber in a black prevents dirt and water into the speaker's floor.
The pores on the face.A tune for proper. There must be designed and calculated.On the part of the inside of the fiber sheet black the dirt and water into the speaker again.