No one actually knows how to lculate what speaker cable they need

Mr. twoleftears

A 4/0 AWG or 0000 AWG has a cross section of "only" 2x a 0 AWG as well as better resistance.
By the AWG table, the steps between two consecutive AWG cables is not twice as good resistance.
When I write 2x 0 AWG, I meant two 0 AWG cables in parallel.
When I write 4x 0 AWG, I meant four 0 AWG cables in parallel.
If you could use two mono blocks, placed next to the speakers, or back to back, it would be way thinner.

When someone have a fireplace between the speakers and requires 20'+ to make the distance between the amp. and the speakers,

It takes the extra thickness, to compensate for the length.

The cable resistance formula: R = ρ x L/S when ρ is the cooper conductivity (1.68x10-8), L is the length in meters and S is the cross section in square mm.

If length gets twice longer, so needs the cross section, to keep the same resistance:  R

OK, had to run an errand, so I stopped in Home Depot to check out 0 AWG wire.............Smallest/largest they had on hand was 2 AWG.............My God, the stuff is huge, heavy and stiff and this was stranded, sort of..............I'm not an electrician, so I wasn't quite sure what to expect. The biggest stuff I've used around the house was 10 AWG.........Cut a couple feet of this stuff and you could beat somebody to death with it!!.......I can't begin to imagine how you would properly connect it to binding posts or terminal strips.................Did I mention that it's huge?         and that wasn't even the 0 AWG I went looking for......Amps and speakers, at least the ones I've seen and own aren't set up for anything nearly that big, heavy or stiff...............Hope you have a workable fix for that little problem b4icu!!...................The upside is that it's pretty inexpensive by audiophile standards, especially if you can keep it on the shorter side. At least from a cost perspective it would be a reasonable experiment.

Quick check of car audio sites has "speaker wire" in the sizes we're talking about. The stranding is very fine and likely to be much more flexible than what I saw at HD today. That had 19 strands, each of which was quite thick and not bendy.............The weight and size will still be about the same I guess............0 AWG is still 0 AWG..............Starts to get a bit pricier though since now we're talking about speaker wires Vs welding cable!!......Anything "special" costs more :(

Sonicelectronix.com............NVX "0" AWG, OFC, high flex, silver tinned. On sale $170 for 50 foot roll, free shipping.......Any takers?

I've found a seller in the UK (chameleoncable on ebay) that sells 0 awg OFC copper cable. b4icu was kind enough to advise me that my set up (classe ct5300 -> B&W 802) would need 4 awg.

I've spoken with the seller and he'll make me up 4 x 2.5m 0awg cables with spades on each end for around £150. I think that's not a bad experiment for the money. My amp and speaker terminals are all at floor level so the weight won't be a problem.

If there's no sonic difference from my Van Dam blue 4mm, it should look cooler using 0 awg cable!

And if that doesn't work, I've also ordered some of that 12 awg silver cable mentioned earlier in the thread. Again, $120 for 10m of cable, you can't really go wrong.

Once I've had them made up and I've tried them out I'll post my findings. by all accounts I'm looking at a 60% upgrade.