Azimuth and the Fozgometer

I have the Fozgometer. It's a great tool and I recommend it. It seems like this tool still just isn't enough for some, because of the tone used to test at etc. But, put it in perspective: EVERY adjustment on a turntable is an approximation. Alignment is an approximation (pivoted arms), VTF (subjective for sound), VTA/SRA (no standard), and now azimuth. So really, theres no such thing as an absolute setting for any of this. The Fozgometer is reliable and the simplest way to get azimuth as close to ideal as possible.

the simplest way to get azimuth as close to ideal as possible.

Maybe for some.

Does anyone know if the fozgometer measures millivolts and compares them from side to side? If so, then couldn't one just use a millivolt meter or a oscilloscope to measure each side and adjust the azimuth until the voltages are the same? Or does the fozgometer measure something else?

Capnbob,

I believe the way this is done "manually" is to convert millivolts to db, then you would do a left minus right and right minus left calculation to determine crosstalk. A straight reading of channel output would not account for channel imbalance. Also, it is possible that the Fozgometer does more than just measure voltage output (e.g., it could include filters to attenuate frequencies outside of the 1khz test signal so that the effect of extraneous surface noise is reduced. I don't know if this has actually been incorporated in the design, but, I do note that the needle does not jump around a lot whereas readings done with a VOM are more equivocal. I also don't know if the Fozgometer does or does not incorporate some kind of analysis of phase relationships (aside from doing the L-R and R-L), but that is possible since Fosgate is an expert in that field (one of the pioneers of early SQ matrix form of four channel sound).

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.