Shielding methods?

[mr_fender]

Shielding the pickup itself can cause high end loss, but I've never heard of cavity shielding audibly affecting the tone. Metal pickup covers like on covered humbuckers and Tele neck pickups can kill a little bit of the high end. I've read it has something to do with eddy currents being created in the cover since it wraps around the pickup like turns of wire around a pickup. Same thing can happen if you wrap a single coil with shielding tape and ground it as well. You're supposed to leave a small gap in the loop of tape to stop any eddy currents from forming.

 

[Andy Eagle]

Shielding pickup cavities is the same effect. Control cavities don't do it but with good parts and a screened output you won't need it anyway.