Yeah, there's really too many variables involved. Not only different lengths, but different gauges.

Also when testing how much of an increase in resistance (or impedance) there is from bare wire to terminated wire, the connection point to the test equipment needs to be controlled.
Pioneer VSX-1018AH-K, PDP-5020FD, DV-79AVi
Axiom M22s, VP150, QS8s
Sony PS3, surround backs