I have done some calculations on speaker cables that I will share with you. With the calcs, you can make a scientific decision, which is bound to be the soundest method given the price of cables. Each cable will have R (resistance in ohms/length), L (inductance in Henrys/length), C (capacitance in Farads/length), and G (Don't know what the G stands for, but it represents resistance across the dielectric that separates ground from signal in 1/ohms/length). Based on these 4 variables you can calculate dB loss over the entire frequency range. One caveat, these calculations do not take into account skin-effect increase in resistance with frequency. Suffice it to say that the skin effect is less with Kimber 8TC that I compared with Monster XPHP. I had some surprising results, which in retrospect make perfect sense. Now, the biggest problem is that most manufacturers do not give you the R, L, C, G of their cables. I have 2 PDFs by Niel Pass and Hansen who measured these variables. PM me if you would like to have these pdfs and Id be happy to forward them to you.
For simplicity (I could not paste the graphs, which is in Excel) I have provided dBloss at 100,000Hz, way past the audio band, but it increases differences. Differences are smaller at 20 KHz, but the pattern is the same, and I am not sure what -0.5dB loss at 20 KHz translates into in audiophile language: perhaps less 'air'!
8TC is 9AWG 16 stranded copper weaved (8 pos, 8 ground) with strands electrically isolated.
Monster XPHP is 11.5-12 AWG copper
One final note: The more copper the better at low frequencies, below is only results for high frequencies
8TC 5m
-0.29 dBloss
Monster XPHP 5m
-0.82 dBloss
8TC 5m + 8TC 5m (Biwire)
-0.29 dBloss !! no different than one run of 8TC (The bottom end would have a much higher damping factor, but no diff at high freq)
8TC 1.55m
-0.03 dbLoss !! (length matters: experts keep saying, shorter is better -- here it's logarithmically better)
Monster XPHP 1.55m
-0.46 dBloss (pretty good for cheap cable if it is short)
There you have it. Keep it short for speaker wire, don't forget the low end where more copper is best, and you should be OK with the high-end. Having said all of this I have 10 foot run of 8TC supplemented with 2 runs of Monster XPHP. I am rearranging to cut the wire-lengths to 5 feet each by moving the amp in between. If I were to buy today, I'd invest in Bryston 9AWG 5$/ft after I ran the RLCG through, but I doubt the performance would be worse than Monster.
Cheers,
Shafie