Do cables really need "breaking in"?

first i couldn't believe cables sounded different--it didn't make sense.

but they do.

then i doubted that they could break in.

but they do...some more than others (i.e. silver cables change substantially compared to copper)

rhyno

Theoretically Yes.
It can happen that you won't have to break them in but that's rare.
It can happen that you won't hear the difference between cables that had been running for 200...800 hours and brand new.
A conductor's break-in process is to direct electrons to the "right path" with minimal energy loss.

In bunch of cases breaking-in cables with your home equipment will bring you no success throughout long time of listening since breaking-in process might require much higher current to "straighten out" dielectric or semi-conductor nature inner impurities randomly residing inside the conductor.

More likely it was invented by cable purveyors, who wanted to discourage returns. "Don't like it? Let it break in some more." I've never heard of a properly controlled comparison of old and new cables, though you can expect lots of personal testimonials to follow.

Given that there is no permanent physical or chemical change to cables resulting from their use, the most likely explanation for any perceived change in sound over time is, as you say, psychological. And your final point is a good one, too: There are too many confounding variables to draw any conclusions about how a cable's sound changes over time, even if it does. But that never stopped anybody.

It is possible to argue that the properties of the dielectric change with increased use. I don't know whether this is audible. Given that audiophiles can hear the difference between different cables, it isn't inconceivable that break in could be audible. Audibility can manifest in a variety of ways.

People hear things in different ways. I always used to listen for frequency response effects when switching components -- cleaner highs, tighter bass, smoother mids, etc. My first experience hearing a cable change was a little startling. I had a high quality recording of a jazz trio that I knew well. With the music playing in my family room, I could imagine the trio in the family room when I was in the adjacent kitchen. But when I walked into the family room, I could tell they weren't there live. After I upgraded my speaker cables, I couldn't hear any frequency response differences, but this recording now provided a "same room live" illusion -- if I closed my eyes, I could imagine them in the room with me! I've been a believer in quality cables ever since.

Some discussion of cable break in from an engineering point of view is provided in Audioquest's cable theory treatise at www.audioquest.com. Check out Cable Theory page 5. Happy listening!

interconnects are the most sensitive to breakin & can take several hundred hours, speaker cable not quite as long. You won't believe any of this until you hear it yourself though. I once tried to return some expensive ic's but the dealer talked me into waiting a month & I'm so glad that he did. AC cords don't seem to change much that I've noticed, but others report differently & who am I to argue?