Dear Brian,
Doug Deacon and I agree: Azimuth does not have much effect on channel balance. But I am just a shlub. Don't take my word for it, although I did experiment with this just to prove to myself that it is true. Using the suitable test track and my Signet Cartridge Analyzer, I was able to demonstrate to myself that changing azimuth from one extreme to the other, using my Triplanar tonearm which has easily adjustable azimuth, had a less than 2 db effect on channel balance, and to get that much difference, you have to go to ridiculous extremes with the azimuth setting, as much as 10 or 20 degrees off the vertical. Also, if you go to Vinyl Asylum and search the archives, you will find white papers on azimuth by both Victor Khomenko (chief engineer at BAT) and by Brian Kearns; these make similar statements vis a vis channel balance. Those two treatises plus the experiment I personally conducted are the bases for my statement. Please tell me why you disagree, with some supporting data or a reference, if possible. I am willing to be proven wrong, but not by a mere assertion from you.
By the way, it would seem that the OP's own results support my thesis. He admits that he made large changes in azimuth, and it had little to no effect on channel balance. For this he blames the Fozgometer. My point is that he should not have expected azimuth to affect channel balance. Thus the Fozgometer may not be defective at all. I think this is Doug's point, too.
Doug Deacon and I agree: Azimuth does not have much effect on channel balance. But I am just a shlub. Don't take my word for it, although I did experiment with this just to prove to myself that it is true. Using the suitable test track and my Signet Cartridge Analyzer, I was able to demonstrate to myself that changing azimuth from one extreme to the other, using my Triplanar tonearm which has easily adjustable azimuth, had a less than 2 db effect on channel balance, and to get that much difference, you have to go to ridiculous extremes with the azimuth setting, as much as 10 or 20 degrees off the vertical. Also, if you go to Vinyl Asylum and search the archives, you will find white papers on azimuth by both Victor Khomenko (chief engineer at BAT) and by Brian Kearns; these make similar statements vis a vis channel balance. Those two treatises plus the experiment I personally conducted are the bases for my statement. Please tell me why you disagree, with some supporting data or a reference, if possible. I am willing to be proven wrong, but not by a mere assertion from you.
By the way, it would seem that the OP's own results support my thesis. He admits that he made large changes in azimuth, and it had little to no effect on channel balance. For this he blames the Fozgometer. My point is that he should not have expected azimuth to affect channel balance. Thus the Fozgometer may not be defective at all. I think this is Doug's point, too.