When my system used to be analogue, I was running Dynaudio Audience 122s which were harsh as you like. Cabling made no difference whatsoever. I changed to B&W 705s and the harshness was much much less. I'd suggest cabling isn't where the issue lies.

Chris
Srces: Wiim Pro | OSMC Vero 4K+
Procs: HD621 > G61R > Minidsp DDRC-88D
Spkrs: 7200.2 + 5KC + 5Ks | iNuke6K > USC15 | iNuke3K > 2 x Crowson T108SS
Video: JVC HD950 & 1.9m React3 2.4:1 screen
Room: 5.8x2.8m | Various GIK Panels