Math + Logic + Science = something completely mad...


So, I've done a metric fuckton of research, notwithstanding the clear bias the man who designed and built my Belles has against esoteric cabling.  And here's the conclusion to which I arrived. 

My monoblocks are sitting on top of the speakers.  The distance from the amp to the speaker is barely a foot, which is exactly how long a run of wire I intend to use.  Goal is to minimize the effect the wire has on the sound.  

According to the calculations I've seen and done, the skin effect depth on copper wire at 20Khz is 461 micrometers.  Meaning a 19-gauge copper wire (911 mics diameter) would reduce skin effect to zero.  As in no impact whatsoever on the signal. 
 
Of course, it's actually very difficult to find 19-gauge wire.  18-gauge (1024 mics) is much easier, and the skin effect is near zero, but not quite zero.  Seems to be an acceptable compromise. Could go down to 20-gauge and eliminate skin effect entirely.  If I could find insulated aluminum wire, 18-gauge would eliminate skin effect entirely, because skin effect depth on aluminum at 20khz is 580 mics.  

12 inches of 18-gauge wire produces 0.006 ohms of additional resistance.  20-gauge = 0.01 ohms.  

Frankly, I don't see the value in spending big bucks on esoteric, heavy-gauge wire for this application.  I'd rather make the bigger investment in the 2m runs from the preamp to the blocks, because that's where the wire's going to have a hell of a lot more of an effect on the sound.  

Stepping back to allow you all the opportunity to punch holes in my thought process here. 
jerkface
dletch2, I remember long time ago I had inexpensive cable from Best Buy. I believe it was Monster Cable brand. It consisted of two parallel runs of very thick stranded wire in thick clear plastic (most likely PVC) insulation. It was suppressing high frequencies to a such degree that I had to add few dB of the treble on my receiver. Later I replaced this cable with AQ Indigo and magically treble came back (everything else being the same). Indigo was OK, but Acoustic Zen Satori that replaced it is in different league. What surprised me the most was lower midrange (cello, chestiness of male voices) that got fuller. In comparison Indigo sounded thin. I would not even try to express it in electrical terms. Since then everything else changed in my system for the better, but speaker cable is still the same. My hearing was not that good because of age, but I could still hear a difference between AQ King Cobra and Acoustic Zen Absolute interconnect that replaced it (foam Teflon, oversized tubes, Zero Crystal silver). It is cleaner, faster, darker background, more instrument separation. Why? Is it because of insanely good specs (6mohm/ft, 6pF/ft, 20nH/ft)? Calculations would likely suggest that both interconnects should sound exactly the same, but they don’t.

AudioQuest FAQ explains logic behind helical twist on oversized air tube. They stated that in order to avoid skin effect wires have to split into separate insulated strands, but then skin effect still applies since they are in magnetic field of each other. Remedy for that is to place them on the tube. That way each wire is only in magnetic field on neighboring strands. In addition it is interleaved with return wires to reduce inductance and twisted to reduce electrical pickup. That is exactly how my Acoustic Zen Satori is made. Different companies and the same design? Are they all doing it for show? Is it snake oil? I have pretty good understanding of electronics, but getting much deeper into something requires different expertise. I believe that we don’t even comprehend exactly the nature of electrical current. We know that it is motion of electric charge, but how energy can be delivered to load if exactly the same amount of electrical charge comes back by return wire? Why energy flows toward load while AC electric charge flows back and forth? Energy has to flow differently and it does - by magnetic filed outside of the wires (Poynting Field). Do we now understand everything? I remember some horrible amplifiers in 70s that had extremely low THD and IMD (achieved by deep negative feedback) and sounded bright and tiring. Later Transient Intermodulation (TIM) distortions were discovered. That makes me believe that trusting my own ears and cable companies is perhaps better than trying to make sense of it. I selected Acoustic Zen instead of AQ because it is better bang for the buck, IMHO.
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So how come whatever wire you use can make a big difference to SQ.
Because, as I've said elsewhere, there's no such thing as "perfect" wire.  Just trade-offs. More inductance in exchange for lower resistance and capacitance.  Less inductance in exchange for more capacitance.  

Even the insanely expensive stuff still trades one problem for another.  How big the problem is and how much it affects your system is what will make one cable sound better than the other.   

But it also means, depending on the application, that a $25K cable will be outperformed by a $20 one. 
Oxygen free copper is nice to reduce corrosion, but never mind OFC or OCCC failing in blind tests, or silver

Silver is a mind-blower for me.  Because silver creates its own set of problems in terms of signal conductivity.  Sometimes I wonder if there's just an opulence aspect going on there.  Like, if a manufacturer thought they could make it cost-effective (for them, not for you), they'd put out a 14k gold wire, just to see if it'd sell.  

In fact, I seem to recall back in the 80's reading a Stereo Review article about gold speaker wire.  But I couldn't say for sure who did it or what purity level it was.  

We end up where we started R, L, C.
And now comes the money question.

Presuming that I shelve the amps a few inches above the speakers (already bought shelf kits to do this), now I still have my 12-inch speaker cable run, BUT, I still have 2.5 meters between the amps and the pre.

So now I have a milliwatt signal being broadcast on a longer run than the high-watt signal between the amp and the speaker.

It seems to me that C should be my biggest concern when I contemplate my interconnect choices due to the longer run, though RCA cables tend to be far less transparent regarding their specs than basic speaker cable.

Your advice would be useful here.