Jeff_jones... Traditional "measurements" usually report specific characteristics of the signal. The measured parameter can remain unchanged while other parameters change, and affect the sound. The significant parameter for audio is "how it sounds". and the best measurement instrument is the human ear. There is a way to make the ear measurement in a completely objective manner.
In the case of an interconnect...
1. Input a common signal to both channels of your system. You can use a real music signal.
2. Adjust gains and, if necessary, frequency response so that the signal measured across the hot terminals of the amps is zero ( a null). You can make this measurement using a meter or scope. or by ear using a headset.
3. Insert an extra interconnect in one channel.
4. Repeat the null measurement of step 2.
If the null obtained in step 4 is the same as step 2 the interconnect has no effect.
In the case of an interconnect...
1. Input a common signal to both channels of your system. You can use a real music signal.
2. Adjust gains and, if necessary, frequency response so that the signal measured across the hot terminals of the amps is zero ( a null). You can make this measurement using a meter or scope. or by ear using a headset.
3. Insert an extra interconnect in one channel.
4. Repeat the null measurement of step 2.
If the null obtained in step 4 is the same as step 2 the interconnect has no effect.