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

I just want to listen to my music. I like what Steve said. And I dont want to spend a ton of cash on cables. I do understand powering my equipment.  Mainly the amp. I have 4 double gang boxes on the back wall, each is a 20 amp circuit. So my amp is dedicated to a single circuit. I will eventually use a 12 awg cord to get the full power from the circuit.  I do understand one thing about electric,  the long you run the thicker the awg. 12/2 is in the wall and going any larger will not get me anymore power. Actually it would be dangerous to go a higher awg off the wall, don't want to heat up the lines in the wall. 20 amp from the breaker is all u will ever get and 12/2 is the feed. 12/2 does have distance limits. Unless u have 10/2 or 8/2 in your walls which no homes have except for dryers, ovens. Or you ran your own wiring. I know we are talking about speaker wire. But I thought I would throw in my electrical experience.  My 2 cents.