Some good points, Michael, but a couple of them need further discussion. The peak-to-peak voltage of the nominal 120V AC waveform is actually about 340V, rather than 169V; the peak voltage is +170V rather than +85V and drops to -170V. As you point out, the nominal 120V figure refers to RMS(root mean square) voltage, not peak voltage. The relationship between them on the AC waveform is that peak voltage is 1.414(square root of 2)times the RMS voltage, which is a type of average voltage, but calculated in a special way: the values of the voltages are squared and then added and averaged, with the square root of that average then being used as the RMS value. Seems like a lot of work, but the computer doesn't mind, and the RMS voltage is generally accepted as a more effective measure for use in power calculations than either peak voltage or a simple average.
As I previously commented, speaker wires are essentially immune from interference in home usage and no special shielding or precautions are necessary. For example, Blue Jeans Cable points this out at the beginning of their speaker cable
discussion . What has to be taken into account is that the current in a speaker wire is on the order of a thousand times stronger than that in an interconnecting cable operating at low voltage into a much higher impedance than the speaker impedance. It would take an extremely strong electromagnetic or radio frequency interference field to cause a problem with speaker wire, and these almost never would exist in the home. So, the precautions listed, which are often suggested for protecting interconnecting cables, especially if they're not well-
shielded, aren't necessary for speaker wire.
