how can a line cord affect frequency response ?

i have personally auditioned over 10 different manufacturer's line cords. i hear differences. i don;'t understand how a line cord can affect treble response or bass response.

can someone provide an explanation ?
That was hilarious Guidocorona.
Perhaps it's best to split this thread now into two distinct subjects:

1) the line cord frequency thingy
2) proposed new branch:
"How a technical discussion affects the mental status of Audiogon members" included we have a cast of mechanical froggies, psychologists, lawyers, philosophers, fisherman, and the impatient

If you are looking for good natured humor choose path 2.
If, however, you don't mind technical details and perhaps dry humor choose 1.

Your river analogy is very good but what happens upstream of the audio component is all very criticial. As per Ridgestreet, there is a coloration on all the rest of the chain from the foundation up; the power supply gets modulated by all other circuitry.

I used to live in an area where my electricity came from a coal fired power station; the sound was smoggy and lacked clarity. Since moving to an area with gas fired electricity the improvements are astounding....crystal clear clean sound!

If any of you have heard exotic Power Cords that made a big difference just consider what enormous improvement can be attained from having your electricity generation come from clean gas or hydroelectric rather than dirty coal! One day I intend to hook up solar panels to power my gear for that last extra step to audio nirvanna!
I've been using solar power to re-charge my battery operated system for years.

Just for a little aside to the discussion here, I don't use "audiophile" AC power cords. My system is battery operated on DC power.

And I use a separate 12vdc lead-acid type battery and very short cabling for each individual component. There is no interaction between the power supplies of my components, except for whatever interaction occurs between the components themselves via the interconnects. My amp power draw has no effect on the power supply to my preamp, or to my turntable, and vice-versa. Also, high-voltage electromagnetic fields associated with the AC power supplies is virtually eliminated.

I find this works very well for me, but may not be suitable for others, especially those with high power audio systems.
Now we have a start for the "my electrical station is superior to your electrical station" thread.

You just made PS Audio very happy. Everyone quick flock to PS Audio website and drool over the latest line conditioners.
Point well taken Dpac996, I admit I have had fun enough for a spell. I will now go back to passive SONAR mode!