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

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

Hi Steve
What amplifier and speakers do they connect?

What makes you think that you got the right cable now? 
This is a blind shot in the dark as all other cables before. 
You still may have a cable that is not getting the best out of your speakers. You just don't know that.

Bo1972 does