By Bryan Geyer
I suggest AWG 12 stranded all-copper (not copper-clad aluminum*) duplex wiring for your power amplifier-to-speaker cable runs. An excellent version is made by Belden, and it’s available from Blue Jeans Cable; refer https://www.bluejeanscable.com/store/speaker/index.htm. Their “Twelve White” is a premium AWG 12 stranded copper cable (Belden 5000) that’s optimum. It’s properly insulated, and exhibits less tendency to kink than the imported AWG 12 wire sold by many retailers.
Despite what you hear to the contrary, it is neither necessary nor beneficial to maintain identical linear lengths for the left and right channel wiring runs. Given the speed that electrons travel, there will be no audible phase delay difference if one stereo side has a longer wiring run than the other side, nor will there be any difference in signal amplitude that might theoretically arise from some niggling variance in series impedance. Cut the cable lengths to fit your personal layout preference.
Do not consider any of the esoteric speaker cable that’s promoted within the hi-end audiophile community. As noted by Peter Aczel, who founded The Audio Critic…
“The transmission of electrical signals through a wire is governed by resistance, inductance, and capacitance (R, L, and C). That’s all, folks! (At least that’s all at audio frequencies. At radio frequencies the geometry of the cable begins to have certain effects.) An audio signal has no idea whether it is passing through expensive or inexpensive RLC. It retains its purity or impurity regardless.”
More good info at: https://www.audioholics.com/audio-video-cables/speaker-cable-gauge.
The basics are well summarized at this classic site: : http://www.roger-russell.com/wire/wire.htm.
If your power amplifier and loudspeakers both utilize dual banana jack posts (with standard 19 mm [0.75 inch] on-center spacing), terminate your wiring with compatible dual banana plug connectors. Some nice gold-plated dual banana plugs with helpful bottom entry wire access (minimizes the rear clearance) are available from Parts Express...
For right (red): http://www.parts-express.com/gold-dual-banana-plug-red--091-332
My preference is to shorten these dual banana plugs by discarding their fancy knurled end posts and substituting #8-32 x 0.75 inch flat point stainless-steel set screws; see https://www.mcmaster.com/set-screws. Drive those set screws with a 5/64 inch Allen hex wrench—or with an equivalent 5/64 inch hex bit (more elegant) from Chapman Manufacturing Co.; see http://chapmanmfg.com/. (If you admire fine hand tools, get to know Chapman.)
*Lots of retail “speaker wire” is now copper-clad aluminum. Suspect sellers who shout “pure copper”. Their boast might relate only to the cladding—not to the core. (Hey, I may be an over-the-top skeptic, but do be wary of bargain wire!) FYI: 100% all-copper AWG 12 wire exhibits DC resistance ≈ 0.016 Ω per ten (10) linear feet. Use a 4 1/2 digit mode meter (e.g. Fluke 87) to read cable resistance. Measure in relative mode, and test 50 foot lengths that are serially-shorted to net 100 linear feet of conductor. Example: Minimum readout on the Fluke model 87v meter = 0.1Ω, with accuracy of ±0.2% + 2 counts. So 100 ft. of AWG 12 all-copper wire ≈ 0.16 Ω.