It is likely easier, in an objective sense, to measure the signal at teh speaker terminals. Than using the sound itself.
It may be easier in an anechoic chamber as we at least get rid of the comb of the multiple bounces.
To be clear, I’m not saying measure the cable, but record the sound and eliminate what is the same. Those audible differences can be measured. (Hell, toeing a speaker out on one side can be measured, so why not this?)
That is a case in point, where the signal is identical, And can we detune highs and increase the reflections, by decreasing the toe in.
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