Originally Posted by commsysman
0.2 ohms of wire resistance, when connected to a 4 ohm speaker, is 5% of the impedance of the speaker.
This simply means that you will have a 5% loss in the wire, and have to turn the volume up 5% higher. Big freaking deal...lol.
With a double run, or 14 gauge wire, you will knock the loss down to 2% or so.
The problem with too-thin hifi speaker wires is not overall sound loss, but differential sound loss at various frequencies.
If the problem were due to overall sound loss, the too-thin cable could be compensated for over a wide range by simply turning up the volume a little more.
Most speakers, as is correctly pointed out in post 6 have a frequency range where their impedance is minimum, while the impedance of the same speaker is much higher over broad ranges at other frequencies.
The cable's resistance usually causes far more loss in the range of frequencies where the speaker's impedance is minimum or close to minimum. The cable's losses over the range where the speaker's impedance is higher is often much less.
The difference in the cable's loss in different frequency reanges is the essence of the problem. If the difference in the losses is large enough then the sound of the speaker may be audibly colored by the cable's excess resistance.
This same problem can be caused by certain tubed amplifiers that may provide even higher source impedances than the wire that we are talking about right now.
5% loss corresponds to a 0.5 dB loss which is possibly audible, but rarely if ever an actual serious sound quality problem. Modern AVRs with automated system optimization facilities may address problems like this or even far worse as part of their normal operation.
Therefore the basic advice that a speaker cable with only 0.2 ohms or less resistance will cause no serious problems with a reasonable worst case speaker that dips down to 4 ohms is basically good.
However I thought this was a good opportunity to clarify the basic goal of the discussion, which is to produce high fidelity and minimize audible coloration.