Analog Magic Question

Ironically, the way we vinylphiles use the term”zenith” doesn’t conform to any conventional definition of the term.

"In theory it should if the effective mass is low enough to render the resonance frequency of the combination using an LVB is in the 8-12 db range in both planes."

As I am sure you know, frequency is measured in Hz, not in db. So it might seem you meant to write that the amplitude of the resonance is 8-12db. But the desired resonant frequency is also said to be in the 8-12Hz range.  So I wonder what you actually meant to say.

Also, further up the thread, you wrote "Azimuth L to R. 0.03% difference (note my VTA adjuster is frozen but visually it looks OK)". What does that mean? Does it mean that there was a .03% difference in interchannel crosstalk, in terms of db?  That is a very very tiny difference that I doubt can be measured reliably.

Some months or a few years ago, Dave Slagle was at my house, and he adjusted my ART7 cartridge to correct for its zenith error. To do that, he had with him a laptop with some sort of measuring program on it. But also we listened after each tweaking of zenith (made by twisting the cartridge in the headshell).  There was a profound positive difference both aurally and by computer measurement, when he got the zenith optimized.  I was really rather amazed. Since then, that headshell and that cartridge are permanently mated, so far as I am concerned.

So what does Wally or Analog Magik do to correct Zenith error? I have heard talk of a shim, in the case of Wally, but I don't see how a shim can correct zenith.  Seems to me you need to twist the cartridge with respect to the long axis of the headshell in order to bring zenith error down to zero or close to it.

Bill, when you mention azimuth, are you aiming for equal crosstalk in both channels by electronic measurement, or are you aiming for setting the stylus square or symmetrical with respect to the groove walls?

Most cartridges will exhibit at least some zenith error.  Parenthetically, for those who don't already know, zenith for us audiophiles refers to the angle that the stylus contact patches for left and right channel information, respectively, make with the groove wall.  Someone else quoted the industry tolerance for a +/-5 degree error, which is huge. Because of zenith error, any subsequent effort to "zero in" on the alignment of an overhung, pivoted tonearm is folly. You won't get the null points where you think they are, if indeed you get any null points at all on the playable surface of the LP. So, for me, once you've set overhang and VTA, the most important thing is to correct for the inherent zenith error built into the cartridge.  And yet, only Wally has marketed a tool to correct it, so far as I know, and I have heard that the tool is difficult to use and/or may require sending the cartridge to Wally.  But if you are finicky about alignment, you gotta face the music.