What's that installed on the speakers bindingposts?
I think it is a synergistic research "XOT." Here is what they say about it:
"XOTs are parallel filters for speaker crossovers that terminate directly to the leads of your speakers. XOTs deliver a significant increase in resolution accompanied by a lowering of your systems noise floor for more holographic sound. Terminated in either spade or banana connections, XOTs are sold with a no-risk 60-day money back guarantee.
Synergistic Research XOTs deliver:
- a significant increase in resolution
- a lowering of your systems noise floor
- more holographic and natural soundstage
XOT Carbon - Crossover Transducer
Come in pairs with spades or banana termination, for bi-wire configuration you'll need two pairs. MSRP is $449/pair with a no-risk 60-day money back guarantee"