Yes chesseroo, I use only standard 16 ga lamp cord, but I agree that if present or probable future uses would indicate a heavier gauge that it would be wise to use that now. On the possible 50 foot run point( I have nothing nearly that long)the loss for that length of 16ga using 8 ohm speakers is about 0.4 db for the entire 100 foot round trip(the loss for 12ga would of course be proportionally less at about 0.2 db). Losses of these magnitudes wouldn't be perceived as actual volume differences, but could possibly be perceived as a slight quality difference in favor of the higher level( this could be "corrected" by a miniscule increase of the volume control).
In addition to a simple loss of volume, excessive speaker wire resistance could possibly interact with the output impedance of the amplifier to cause variations in frequency response as impedance of the speakers varied up and down. Alan pointed this out in his 8/13 reply on Technical Questions to the question about unequal cable lengths. This is more of a problem with tube amplifiers, which have a much higher output impedance.
