how can a line cord affect frequency response ?

>>". . . restricted or unrestricted flow of electrons."<<

***What does this mean, and how is it measured?***

You'll need an electronvelocitormeter. Available at better auto parts stores, it will also enable you to adjust the proper level of headlight fluid in your car.

**I forgot to check my headlight fluid the last time I put water in my tires.**

You're poking fun at a very serious situation here. Recently an AC worm infiltrated my power conditioner rendering it useless. Before I became aware of that rascal, it had also infected my power cords totally disabling them. The copper and gold conductors had turned to lead. I'd advise all readers to install a firewall on your power conditioner and dutifully monitor your electron speed. Forewarned is forearmed folks.

**do you know if Ortho "Bug-Geta" Snail Bait will work on the AC worm?**

This is undoubtedly the most meaningful thought you've posted. The answer is, I'm not sure. The first thing I did was spray the entire power delivery components with Round Up. Then I installed a wind powered generator and converted everything to DC. My electrons were not up to the challenge of changing direction 60 times every second so I made it easier for them; nothing to think about just look straight ahead. Now they all move in the same direction, at the same time, in lock step.
Lastly I made the switch to dedicated DC lines and DC power cords.