Speaker cable length.

Thanks guys. Makes sense. I already ran the cable since the contractor had to run electrical underneath for the same reason.  The holes were there so it was simple. Haven't cut anything to length yet.

@carlsbad2 I think many audiophiles would say they could hear the difference between 16' and 4' at 0.5c no problem. Especially if the cable cost less and $100 a foot. ;-)

I would keep the speaker cable lengths as close to equal as possible. As it is under the floor, you could add some hooks to keep it off the floor- but, don't coil it as you might introduce some electromagnetic anomalies.

 Much depends upon your cable and it's design. If it is something like zip cord, then you will probably have issues. If it something using more advanced design, say shielding and dielectric boxes, the results might be more subtle.

Bob

@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.

The audiophile rule of thumb is that always keep both lengths the same. It is one of those things that has never been worth my while to test. It is easier to be safe. There may be many technical reasons not to do it. One is that electrical wire (non-single crystal) is made of thousands of small grains with boundaries and the signal is very slightly delayed by these causing smear. A while ago I actually read a scientific article on this… and it happens differentially across the frequency ranges. So the grains act like little capacitors. Anyway, you can see how across vastly different lengths you end up with different effects between the speakers.

Yes, coiling up wire puts wires next to each other. I am sure Transparent is shielded. I have had a coil or two here and their over my lifetime.
 

I hope this is helpful. 

I’m gonna go with the signal is moving at such a ludicrously fast speed that 12ft. differential will mean the same as zero. Just use the lengths you need to use, no more, no less and save your worries for other things like how the smoke particles getting into your gear is going to affect it.