Speaker cable length.

For many years, in my second audio system,  I am using cables of different length, one is about 3 times longer than another. I used different speakers and amplifiers. I noticed no problem and no differences at all. 

I love chiming in on posts like this!   I’m always entertained by the ludicrous responses regarding speaker cables and all the BS people have bought into and the BS put out by some guy with absolutely no clue wtf he’s talking about.  It’s best to keep cables about the same length but not at all an issue if cables are larger than 18 gauge.   You want to try to keep impedance about the same as a good practice but again, from an engineering perspective not that critical.  

Have you considered that running outside and presumably therefor being subjected to outside temperatures, etc. may result in the cable itself being damaged by the elements and for that reason not a good choice? Understandably you don't want the cable running on the floor in front of the fireplace. However, is it possible to run it underneath a carpet placed in front of the fireplace or, alternatively, can you run the cable unobtrusively up one side and down the other side of the chimney to the speaker. I had to do that in my house and there are ways to make the wire very unnoticeable while you accomplish your objective. Running it behind the molding which likely will line the sides of your chimney can help with this cable hiding effort.

@pmiller115 The cable runs under the house in the crawl space right along the sill plate. So it won't be exposed to wet or sunlight or even extreme temps.

I checked and the cable is 12 awg with good quality insulation around the outside of the 2 wires which also have good thick insulation on them. Where the cable goes down through the floor there is nomex. The speaker cable is only close to the nomex for a few inches and I put a plastic divider between it and the speaker cable.

I cut the short cable at about 4' and the long cable is probably 11'.

I cannot tell any difference in sound quality and did not feel the need to A-B test so I can't say for sure if there is any difference at all. I can say that there is no difference in the level of listening enjoyment............which would probably be a better measure of audio quality than many of the other nuances and descriptors we audiophiles try to convince ourselves are actually objective.

This is a total non-issue. The only effect if taken to the extreme would be to slightly reduce the damping factor. Could you hear it? Well if you measure the DCR of the woofer voice coils you will find a small difference and nobody bothers with that.