Underhung tonearms cannot benefit from headshell offset and so are straight
I looked up Stereophile's review of the Viv Float underhung tonearm so at least I now know the difference between overhung and underhung!
(In the review, Stereophile uses the term Lateral Tracking Angle for what I called Horizontal Tracking Angle. Lateral is a bit too biological for me whereas everybody can grasp Horizontal and Vertical)
Seems to me the arguments for under-hung are quite, well, under-done!
Try this. Imagine a reference line between the tonearm pivot and the stylus. The primary friction force is along the reference line. But any time the groove at the stylus point is not completely aligned with the reference line, there will also be a sideways component, the skating force. This is regardless of the shape of the arm and any offset of the cartridge. It is also regardless of the amount of under- or over-hang. It is simply because the friction force always has a sideways component, except when the groove and reference line are in perfect alignment.
I would love you to invest in a Holbo - which I would call well-hung
because there is virtually zero skating force. If the zenith and azimuth are set properly there should be zero tracking errors, either lateral or vertical. The reference line is the straight tonearm, there is no headshell offset. The entire system costs roughly as much as the Viv Float, I think?


