will different lengths affect sound

Rrog, actually mine aren't equal. They are custom cut to accommodate the in-joist run. I didn't measure them when installing, but one's around 18' and the other probably 23' or so.

Seems to work fine.

I used to have 25' runs of cable to my system. When I was able to move to a 7' run I noticed a nice improvement in the sound (not as rolled off on top and tighter bass).

So something on that level of difference I can understand, but not if one is 7' and the other 8'.

I'm certain that the impact of cable length over arrival time is imperceptible, but not the same could be said about the overall resistance, inductance and capacitance.
These will vary with length and be more likely to produce larger differences than arrival time.
Audible? Some will say 'yes', others 'no', like everything else in this hobby...

Bill, Yeah, I remember Ocos advertising there would be no audible difference in using different lengths of their high efficiency speaker cables.

Does "Nice try though" mean the same as better luck next time?

Not only does Ocos advertise no audible difference using different lengths, they also state that with their cable, there is no difference between long versus short runs. I never tried a short run of their cable, but I use an 18' long run and have been very.