Sound of cables breaking in?

yep, I have experienced all of the above.  Good out of the box, then they got shouty, loud, hard, grainy, or unbalanced, then good again.  I have had bad sounding out of the box, then they got progressively better. 

Another technique that can accelerate break-in is using a Purist Audio Design Ultimate System Enhancer disc.  They claim that for every hour played you achieve 5 hours of music play break-in.  I use that disc to help with burn-in  anything new in my system, including tubes.

Right-O! Not only that but these burn-in CDs like XLO and Purist demonstrate that cables never actually burn in completely without using the burn-in discs, you know, since using the burn-in discs on what are assumed to be very well burned in cables, even ones in everyday use for years, improves them significantly. Sha-zam!! So, how much do cables burn in listening to music? Well, you tell me. My guess is 75% max.

I will limit my comments to quality build cables, because cheap budget cables that I personally experienced max out very early in the process and don’t follow the same observations following

I disagree that any proper or definitive audio performance evaluation can be gleaned from any fast first plug -in /swap-in bake off . It won’t give you any proper gauge of ultimate performance.

It took 350+ hours for my high-end model NORDOST cables loom to break in substantially (90-odd %) of peak performance , and it was not any linear pathway to OZ.

Rather it was an ad-hoc series of incremental steps . There were numerous flat plateau periods, and then I would be pleasantly surprised with another "new" improvement that made it all sound better.

This phenomenon isn't restricted to just cables, new phono cartridges, tube amps, digital equipment, headphones and I can go on and on.