Wayne Parham Messages: 18787 Registered: January 2001
Illuminati (33rd Degree)
The wood plug would probably be fine. Just trying to prevent having an unintended hole in the box where the compression driver was supposed to be.
The voice coil cap is usually responsible for radiating some HF sound, especially when mounted on a horn because it is centered. It also serves to "pin" the center of the cone, providing a structural feature. The attachment to the voice coil is one place where it is pinned, the surround is another, and the voice coil cap is a third (unless the cap is glued on the former, in which case there's only two). So anyway, it does have an impact, sometimes a fairly significant one.