Perhaps the 8 ft reference simply evolved from the average distance people tend to place speakers apart, allowing for plenty of slack so as not to strain the terminals at either end. Just my theory anyway...
You can't make a short cable longer, but if a cable is a little too long, it's easy enough to hide the excess, or have the cable shortened.
From my limited conversations with a speaker cable manufacturer, I've been advised the shorter the better, as this reduces capacitance, resistance & interference.
Then again, I recently shortened my cables by 3 feet with no discernable change to the sound, so who knows?...
You can't make a short cable longer, but if a cable is a little too long, it's easy enough to hide the excess, or have the cable shortened.
From my limited conversations with a speaker cable manufacturer, I've been advised the shorter the better, as this reduces capacitance, resistance & interference.
Then again, I recently shortened my cables by 3 feet with no discernable change to the sound, so who knows?...