thats a fairly substantial difference in cabling length.
Did you detect any kind of signal arrival offset?
Electrons in a cable travel at a speed on the order of the speed of light, so you would never be able to hear any kind of offset. Not motivated to do the math right now, but it would be unbelievably small.
A bigger issue might be the effect of greater resistance and especially greater capacitance in the longer cable, since both resistance and capacitance associated with the cable are related to cable length. The greater capacitance of the longer cable might have noticeable effects on high frequency content for instance.
Cool idea with the taping, if I can remember when I'm home I'll try to download some tracks to listen to (etree blocked at work).