Capnbob, As Larry inferred. There is no doubt that one could do the measurements done by the Foz "manually" with a proper test LP, a fine quality voltmeter, and/or a 'scope. The Foz is a matter of convenience and rapidity, plus you can be uninformed and still get it right, electrically at least. Also, good 'scopes and meters are not exactly cheap. Nor are the brains to use them correctly common among us audiofools. My only questions about the Foz are like those stated by Larry; I really would like to know exactly how it arrives at its "correct" azimuth setting, because there is more than one opinion on the definition of correct azimuth, even in the electrical sense.