Sonic Diff between a 6' 1.8M & 4' 1.25M PC

Is there a difference in sound moving from a 6' power cable to a 4' power cable? I read somewhere that you only hear that last 6' of cable but would like to understand the concept so I can make a more informed decision. Its a hot mess behind my equipment rack and I would like to clean it up but not at the sake a sonic performance.
If you can use the shorter power cable then do it and see if it really matters to you, not some self proclaimed expert. I have seen shorter ones than that and I can't tell you they had any negative impact on the sound, but maybe I am not as expert at critical listening as are others.
I believe your due diligences has led you to two different concepts ...

"Is there a difference in sound moving from a 6' power cable to a 4' power cable"

Here I believe you are referring to the SWR (Standing Wave Ratio) concept .. where the length of the PC will set up standing waves or reflections

The least deliberating lengths to help minimize these reflections are 1.5 meters (5ft) and 2.5 meters (8.125 feet) ... at these length there will be the least amount of reflections to degrade the signal

"I read somewhere that you only hear that last 6' of cable"

Not quite .. I believe here you are referring to the argument about the importance that a power cable can play in your system ... being as it is the last 6 feet in the delivery chain

It is not the last 6 feet but the first 6 feet as it connects directly to your power supply and should be viewed as a part or extension of it

The two sides of the argument are the PC is the last 6 feet of the power deliver chain coming from the power company .. how can it improve the signal after all those miles of wire and contamination coming from the power company

I’m from the school that says it "can’t" improve the incoming signal .. but that last 6 feet “can” definately continue to add additional noise and distortion further degrading the signal coming from the power company

A higher quality PC will degrade the last 6 feet “less” and will sound “better” because it did not inject as much additional noise and distortion into the current vs the amount of noise and distortion injected by a lower quality cable

Shielding .. Geometry and cable length are the variables that can make a difference ... but you can’t improve the incoming signal quality .. only degrade it further
Not much, IMO. Shorter is usually cheaper and better.
I would go 5'! 8^)
If you were to use them without a side by side comparison in a very good system you would not be able to tell the sonic difference. If you replaced it you would not "notice" the change once you acclimated to it within a very short period of time.

If you changed to a different brand/geometry and construction, this would have far more effect than the additional 2m or so.
Shunyata Cobra Zitrons are the same price for either length

It's funny because last night we were having a conversation about aging and the reason we get old is because our cells are constantly losing the ability to regenerate themselves. and while there are things we can do to delay this process ie sleep right, eat healthy etc... cell degradation is going to happen. Otherwise, we would all look young forever. But we could have just as well been talking about power supplies from the electric co.