Longer Power Cords Sound better?


In my quest for power cords, i have noticed that a longer cord say 6 or 8 feet tends to have a nicer sound in my system that the same models that are 3 or 4 feet.
Power cords i have found this to be true include Cerious Tech, Cardas, and VH Audio....anyone have an explanation?

AND by nicer sound I mean they tend to have a richer midrange, and a more coherent top to bottom presentation.
ie
Since this thread is back to my attention today I'll make good on my threat from above, and report that after additional testing with 1.5m vs. 2.5m lengths of a power cord specifically claimed by its manufacturer to incorporate beneficial filtering -- intrinsically via its lengthwise construction, rather than by some sort of discrete attatched filter (the van den Hul Mainsstream, which BTW is not offered in lengths below 1.5m for this very reason) -- I am reconfirmed as siding with the longer-is-better hypothesis (or at least more pronounced in its effects, which in this case I find salutory).
Ehider,

The difficult part of defining "better" PC performance is knowing what is causing the change in sonics from cord to cord. You can't say with certainty that a cable sounds better because it offers 'filtering' of some sort, unless you've compared the exact same cable with and without filtering. Several power cable companies claim that certain of their cords sound better because of a degree of RFI filtering, and yet they also employ other changes on these cords, such as different geometry, different gauge, or even different connectors. When measured, many of these 'filtering' cables have significantly different inductance and capacitance values compared to a basic "diy" cable, which makes it hard to know if you're hearing the filtering, or the increased inductance.
If that seems to leave the issue 'up in the air', I think that's exactly what some of the cable marketing out there seeks to achieve.
Zaikesman,

Did the longer version exhibit less glare, a warmer midrange, and a fuller bass? Or any of those attributes?
I did a lot of testing many powercables. And yess there are cables who sound better when they are longer. Cables of 1 metre comparred to a cable of 2 metres I found out that a 2m cable in many situations sounds better. For example, Nordost starts with 2 metres for there PC's. I comparred a 1 metre with a 2 metre cable. The 2 metre has more drive in the low freq. and the voices sounds more natural. There was one thing the 1 metre was better, there was a little more resolution. We tested on a system of about e 30.000,-
Tplavas: Without going into a detailed characterization of the sound of the Mainsstream (although actually, your adjectives, though not the entire story, do happen to apply very well in this case) -- and I hope without being too cute in answering the question -- the simplest and probably best way I can describe the difference I found attributable to length is that the longer version sounds the same as the shorter version only more so, if you take my meaning. With this particular cord, in these lengths and in my system, to me that's a good thing, but I can also imagine by extrapolation the possibility of going overboard (something that could be said about any filtering). However, without a 30ft. cord on hand to compare that's only a guess on my part, and perhaps as has been suggested things just keep getting better and better, or maybe we simply reach a point of diminishing returns without going over into detrimental effects. (Unlike Leonx, I didn't find any loss of real resolution with the longer cord, although the reduced brightness, which I assume could represent reduced modulated noise, might be mistaken for such.)

PS -- I regret to have to add that for anyone interested in trying this cord, be aware it's a model which has been widely counterfeited on the secondhand market, as I found out the hard way before getting enlightened.