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.
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.