@audioengr
+1
"BTW, brightness is not usually due to acoustics. Its usually something else. Most people go down the garden path using cables that act as filter, ferrite beads or blankets to snuff-out the HF sounds. This is the wrong path to take.
Figure out what components are really at fault. Usually excessive jitter from the source, whether computer or CD player, or poor preamp that adds too much distortion and has poor power delivery or even sometimes a bad DAC. This is typical."
Yup. I would always address what components are really at fault FIRST before using cables to filter the poor sound.
In fact, if special cables are necessary it may indicate a component is at fault or two components are incompatible with each other.