I've been getting some noise in my system after installing a X-over and I think it might be the grounds. On the outside of my X-over it has a screw hole and says GND 8 mm max. Is this another ground for the X-over? If so should I connect it to the ground wire or what? Thanks.

 

Should be no harm in trying. I believe its meant to be an extra ground if you have problems. Just make sure to hook it up near or on top of the nearest amp or radio ground. I don't know where u have things situated but ground them together if possible