Bad Cornwall IV?

Those slate colored things, on the outside of the binding posts, are called "jumpers" they allow you to use a single speaker wire to feed your speaker. When you remove the jumpers, you can use two speaker wires (bi-wire) which people say sounds better.

Note: the binding posts, at least on my Forte 4s, do not allow extreme tightening with spade terminals. You must use banana plugs or your contact is compromised.

Glad to hear you solved your problem!

@mofojo 

I think it’s a Klispch thing. I know another person with new Cornwall’s and a couple with Heresy IV’s that have had issues with the binding posts. Mostly coming loose on the outside and once on the inside.

Take a  look at GR research Youtube chanel and search klipch! 

I have Klipsch Heresy IVs bought new from Upscale a year or so ago and the binding posts are picky!! I had no sound from one speaker, blamed my amp, fiddled and futzed and discovered it was the spade speaker connectors. Switched to bananas via those Audioquest converter plug things and no more problems. I had been about to ship my amp off for service, glad I kept futzing. 

Cornwalls deserve better than an Anthem digital processor. Look to tubes, therein lies your answer….