Length of speaker cables

Shorter interconnects and speaker cables are theoretically better sounding than longer ones, and longer power cables are better than shorter ones (just don't makes loops out of excess cord - it creates a magnetic field). Also, don't run the cords close and in parallel to each other, try to have them cross, if unavoidable, at 90 degrees.

Whether or not you can hear the difference (all other things being equal) may be questionable, but doesn't this business rely on the theoretical, specifications, etc.? 

Psychoacoustics - if you think it sounds better, it does. 

Morrow is the best I've seen. Very good prices, usually there is a sale, or a 40% discount if you upgrade from any cable. They have a very long break-in period so be prepared.

I had mono blocks & went to used Anthoney Gallo 3.1 Speakers with 8 foot high end Silver Plated O2 Free Twisted 12 Gauge Copper Cables (Cables came with the speakers).   I was underwhelmed with the highs, especially Cymbal Sheen.

Later, I built 3 foot long, 5 Strand Pure Silver, (Just under 12 Gauge Total) Teflon coated Speaker Wires & connected them directly to the Mono Blocks.

WOW did the highs ever Jump out & Cymbals had that Sheen, just as in real life.

I do not know if it was the Length or Silver, but the combination was spectacular!. 

Cut in half and biwire.

Have QS mono block 60 watt tube amps with 97.5 dB efficient Speakers tried combination of long IC & short SC & different brands of cables the best I found were boutique cables Zenwave alloy( gold & Silver etc)  & Wywire , I ended up with Wywire all copper Both IC 2 meter 3 meter Speaker cables ( although tried Mogami 1meter self terminated cables ) I don’t like cables that seem to be used as tone control that is what I found with Silver ( bright) or silver gold alloy . The Wywire are very neutral you hardly know they are their in your system