Since the zones are running independent source material using a single channel or amplifier is not possible.
It seems like a waste to use transformers for single speakers but if the 100m cable runs requires it I guess it will have to be.
Interestingly another installer I spoke to swore of the benefits of using shielded speaker cables. I believe, unless I misunderstood him, though, that he was referring at that time to low impedance 8? signals.
So would it be correct to say that with low impedance signals shield cables could offer some potential benefits and with high voltage signals they are not desirable.
While on the same subject what are the potential advantages of standard 2 core cable against 2core twisted pair ?
Suresh Madan