I've found that any cord (or wall receptacle) using silver has an inherent quality that I perceive as brightness, regardless of what position I use it in the system.
I also have dedicated lines but that didn't do anything for brightness; rather it helped reduce the background noise level & allows me to turn on the amp w/o tripping the breaker.
Spkrs can contribute to brightness as well as some components but I use cables to fine tune what I have, so in a sense I consider them tone controls.
You pick & choose what works best for you.
