I added Pangea Audio AC 9SE MKII Signature Power Cable w/ Cardas Copper and it made a significant difference. I am very pleased with these - they are priced very reasonably!
https://www.audioadvisor.com/prodinfo.asp?number=PGAC9S2 Great speakers - which of these do you have?
Martin Logan ESL 15A/13A Non OEM Speaker Power Cables
Has anyone found improved performance from third party power cable suppliers?