How can we hear the difference in cables in a bad room?

Hi after spending the last months measuring my room with REW and reading about room acoustic in small rooms.
I began to wonder how we can hear differences in equipment when the frequency respons in most rooms are bad.

Just think about it! a power cable - why can you hear a difference? is it a timing issue, noise? are the human hearing much more sensitiv to delay / phase issues than frequencies.

If you have knowledge in this area then I would love to be educated (:

Happy new year to all of you.