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

I do believe the word in question is calculate. As I read the comments by the OP and see the obvious errors in spelling/typing, I’m not sure if I could trust the calculations.

b4icu

It goes back to cable manufaturars, mostly provide no relevant data! to sales and the users. None will answer this!

What data do you seek?

What a coincidence. I just came across this site that was recommended by another site:http://www.sengpielaudio.com/calculator-cable.htm

Maybe this can help the OP is determining what he needs.

All the best,
Nonoise

Ok.
Sorry for the speling. English is my 3rd laguage. This site does not allow to copy from word (speler). So you need to be pasined. Thanks.
To exampls:
A PASS LAB 250W power amp, with B&W802 diamond - 3m long:
4 AWG.
An EMOTIVA 250W power amp, with Vienna acoustics beethiven - 2.5m
0 AWG.
The point is that no other is up to the task. The link:  http://www.sengpielaudio.com/calculator-cable.htm deals with interconnect. Not with speakers cables. Ther the parasatic capacitance of the line has a tall on the highs. Balnced lines solve the issue.

I have owned, and in some cases still own, Synergistic Research, Audioquest, Tara Labs, Mapleshade, AntiCables, Van den Hul and (yikes) Monster speaker cables.

And for under $30 I just bought from Blue Jeans Cable Co. 16 feet of Belden 12-gauge 5000UE and 4 pair of gold plated, compression style banana plugs. I cut the wire in half and installed the plugs, installed the shrink tubing, and then hooked them up to my speakers and to my amp in my system paying no attention to "directionality."

These speaker cables sound AS GOOD as any I have owned or listened to previously!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! No break in needed.

Steve