My receiver has two sub woofer outputs, a single line and a left/ring output. My sub only has a left/ring input and instructs that for a single line to use left channel input.
I mistakenly bought a sub woofer cable that splits form a single to a double line. Should I run single line from the receiver into the left/right of the sub, vice versa or doesn't it really matter?
Since your sub has left and right input jacks, you can run a single line from the receiver to both left and right inputs on the sub. On most subs, you'll notice a slight gain in loudness when connecting the them this way instead of using only 1 input jack as per the manual instructions. I think you've made a good mistake when you bought that cable, you do not need to buy a Y adapter after all .