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 (:
People love to make up reasons why. Being at it going on 50 years now my preference is to go with what works. While the rest are enjoying arguing about why I'm enjoying sounds they can only dream of. Actually maybe not even dream. If their imagination is as stifled as their intellect that would stand to reason.
My experience, after trying lots of frankly pretty lame stuff, like a telephone book under or over a CD player, one day got a set of Black Diamond Racing Cones. The improvement with these things was so spectacular I could hardly believe it. Seriously, literally, hardly believe it.
So I started taking them around with me everywhere. Well they fit in the pocket easily enough. Must have tried them under literally at least a hundred different components in almost as many systems. CD players, tuners, tape decks, pre-amps, amps, speakers, budget to extreme high end you name it.
A few examples just to drive home the depth of meaning of "you name it". A Goodwill $5 all-in-one with hair thin wires going to cheesy speakers sitting on the classic this plank across two trunks is my furniture, and this steamer trunk is my coffee table, if you get the picture. A friends Pioneer integrated near the top of a stack of at least half a dozen things (VCR, CDP, Tuner, etc) stacked one on top of the other, rats nest of wires and dust devils behind with two unequal length lamp cords running 20 and 50 feet to speakers in a room with a sliding glass door between them. And one of my favorites, the car audio retailer who let me put them under the crossover network of some speakers on his demo panel. Just loosened the screws, stuck em in there, tightened back down, and heard it.
The friends rats nest was the hardest to hear, mostly because he wouldn't shut up and stop telling me how it couldn't possibly work long enough to hear anything.
Oh and by the way, you asked about power cords. Same deal. Only using Cones because that's the one been tried the most by far. But same exact deal goes with power cords, speaker cables, interconnects. Same. Exact. Deal.
Again, I am happy to let others go round and round endlessly jibber jabbering about why. We report. You decide.
The only answer that I can see that fits all the evidence is the one you already gave: "the human hearing much more sensitiv" which is right, only you then went on to limit this with phase and frequency.
Which may or may not be right. Again, not playing that game. Even if it is probably right. Because why? What's the point? Being able to nail some nerds question on a forum no one reads anyway?
What definitely is true is people can hear these things. Remember I said hundreds of systems? Countless times here is what would happen. The dude who proudly bought it all sits and strains and doubts and questions and goes back and forth. Meanwhile honey in the kitchen who never even came in the room shouts out, "Is that the 4 again? Because his voice sounds so much better with that one! Get the 4!" Dude goes right back to straining, face scrunched up even more now.
Am NOT kidding. Am NOT making this up. Happened so many times its NOT funny. (See: What is wrong with audiophiles?)
The only thing in all of this that makes any sense is things like cones and power cords, fuses, Omega E-mats, TPC, ECT, HFT, Cable Elevators, there are all kinds of different ways they can affect the sound. And you can argue and argue about what they are. Does. Not. Matter! Point is they make an audible difference. Which if honey can hear it, then for sure you can learn to hear it too.