Burn in period

"the ears" might, mind don't. Either you hear it or you don't. It's not an art it's training, like anything else. Knowing how to fix what's wrong with the sound in a system, that's an art. Cables do matter, especially bad ones. How they are handled and constructed, is night and day. It's strange how two simular cables can be assembled by two different people and sound so different.

What is in that cable matters, and the terminal ends are the most important of all. More so than the cable, then how they are joined.. If you can't hear the difference, save your money. Best thing to do. 

I learned with aluminum cable and copper clad. I went from there about 25-30 years ago. A buddy drove me nuts with a system 1000 miles away, come to find out that is what he used for speaker cable. Like throwing a blanket over 10k speakers.

# 12 copper Romex sounded a LOT better as he found out one night while on the phone.

RCA cables are directional if they are designed with shielding connected to ground on one end. Usually that would be your source/signal originating end.

Cable break in is real. I have experienced it with interconnects, power cords and speaker cables.
There are multiple reasons why you wouldn’t hear any difference. In example…you are using stock power cords, interconnects or speaker cables made with standard inferior wire and terminated with crappy connectors. Or your system or a given component is not sensitive to cable changes, or your system is not resolving to let you hear it, or you just simply can’t hear it. It’s like some people are able to smell their piss stinks after eating asparagus while others can’t detect it. Doesn’t mean it’s not a real phenomenon if you can’t detect it. 
 

jasonbourne do you like asparagus?

1. They don't.

2. Absolutely not. As far as electricity is concerned, wire is wire. Marketing BS.

Another myth that needs to be put to rest! Ditto for wire "directionality". Like optical illusions for the eye, the ears are easily fooled!

Well they do BREAK-IN I don't know about burn in. Valves (tubes) burn in and actually burn up. All electronics break-in from the wall socket to the voice coil in the speaker and even the suspension in cone drivers.. 

Of course it makes a difference. It also makes a difference if you condition your cables too. I had copper with silver clad take close to 1000 hours. # 10 large multi-strand that was stiff as a board. They sounded like heaven when they were laid out and let settle. First time I used Russian surplus cable too. Shipping was as much as the cable almost.. Now the same cable is 20 X the cost and 1/2 the shipping and it just went up.. 

As far as direction, look at the wire and see how it was pulled through the die. You'll see the same with crystal wire, they lay in a direction..

I'm not saying anything other than the go go in the cable is doing the cha cha cha in that direction ----------------------------->  and that direction it towards my speakers.

Let that soak into your onion!! That's mechanic talk. :-)

Regards

first one directly gets at what op is asking, second is a nice broader discussion, could be helpful

It has been discussed endlessly. Assuming the cables and interconnects are of good quality as are the components, it does… pain in the butt… I have pursued high end audio for fifty years. You can see my systems, click on my ID.

You’ll get a collection of folk that do not acknowledge it,  half baked ideas why, and a few like me who have heard it hundreds of times, read lots of articles and decided there are just too many variables to concisely answer the question and accept it. I have an inexpensive Schiit system I use to break in power cords and interconnects.