will different lengths affect sound

Audiofeil, And not a single attendee was familiar with the system you mentioned, including AJ Conti.

Both sides should be the same.

A corollary to Kijanki's good comment is that if the longer cable behaves in a neutral manner in a given system (which is dependent on the impedance characteristics of the speaker as well as on the cable characteristics), the shorter one will too!

One thing is for sure, IMO. Timing differences, which were asked about in the OP, won't matter. Electrical signals propagate through wires at a large fraction of the speed of light in a vacuum (186,000 miles per second) at treble frequencies and higher, and even the slowest propagating audible frequency (20Hz) propagates at more than 3000 miles per second. Since 3000 miles/sec is roughly 15000 times faster than the speed of sound in air, the arrival time difference at the listener's ears resulting from a 10 foot difference in cable length would be the same as the difference that would result from his or her head being 10/15000 = 0.0006 feet closer to one speaker than to the other (and far less than that at mid and treble frequencies). In other words, not likely to be audible!

Regards,
-- Al

RE: 6' / 75' and Rrog v. Audiofeil

If the difference in cable length had a serious effect on sound quality, it should have been audible in a disrupted stereo image. Familiarity with the system would not be important.

In a 2 speaker system, the phantom center image and 3 dimensional quality of a stereo recording is created by differences in arrival time, volume, frequency shading and phase balance at the left and right ears.

If the difference in the speaker cable significantly disrupted these qualities, it would be audible in a poor or distorted stereo image.

Not all theoretical differences are audible, even if we'd like them to be.

Rrog - trying to throw some ca-ca into the discussion.

So what that no one knew the system. All these self-professed golden ears should certainly been able to tell if something was amiss, but they couldn't.

Next trial - power cords......