What do you think the "signal" is? And don't forget Ohm's Law...
Also, talking about polarity of AC signals is not technically correct. It isn't like DC. AC signals don't have polarity per se, but rather phase angles. The actual direction depends on the relative complex values of the angles. Remember we are talking about voltage and current information for music and not a single sine wave.
Cable makers should just use a sticker or mark on the end of the cable that has shield ground and tell people that the sticker "should" go on the source side. It would cut down on the confusion the arrow causes people, but it would be more complicated to explain, so I guess they chose the easy path.
Arthur
Also, talking about polarity of AC signals is not technically correct. It isn't like DC. AC signals don't have polarity per se, but rather phase angles. The actual direction depends on the relative complex values of the angles. Remember we are talking about voltage and current information for music and not a single sine wave.
Cable makers should just use a sticker or mark on the end of the cable that has shield ground and tell people that the sticker "should" go on the source side. It would cut down on the confusion the arrow causes people, but it would be more complicated to explain, so I guess they chose the easy path.
Arthur