07-11-12: SunnyjimSunnyjim, I would emphasize my reference to the flatness of the impedance curve I linked to, across most of the spectrum, and to the fact that the phase angle curve (the lighter of the two lines in the graph) does not go significantly negative at any frequency. Those characteristics are probably more important for present purposes than the nominal impedance.
To Almarg, I should have checked with Acoustic Zen about other choices than their own cables, but it seemed pointless in some ways However, your point is well taken, but checking with owners of the same speaker or others that are 5 to 6 ohm impedance. The Adagios are officially 6 ohms.
Most speakers do not have similarly flat impedance magnitudes, and most speakers have impedance phase angles that reach considerably negative values (i.e., considerably less than 0 degrees, meaning they are capacitive) at some frequencies. Sounds like Swanny's speakers might be an exception, which would increase the relevance of his (and DRubin's) suggestion.
Regards,
-- Al