@gdnrbob Can you tell me why I should keep them at equal lengths? What will I notice if they aren't? What should I look for?
If the electricity moves at 1/2 the speed of light (up to 90% according to some sources), the difference in transmission time would be somewhere around 750 millionths of a second (according to my possibly very flawed math). Is that perceptible? Does it cause other issues?
The speaker cable on the right side does not need to go under the floor so if it needs to be the same length, 16' of it it is going to have to go somewhere in the room.
As mentioned, speaker cable is made by Transparent but it is bulk cable. No bricks etc. It looks to be 10 AWG but might be 12.