Discuss The Viv Lab Rigid Arm

Ok I have a theory...

On a conventional arm with offset headshell..if you draw an imaginary line extending the cantilever, past its suspension point, all the way backwards to the plane of the arms pivot point. Viewed from the front of the cartridge, the new ultra-long cantilever will terminate at a point way above and to the right of the arms pivot point.

Now the theory...Attached here is a link that very graphically shows the magnitude of stylus drag. ( I  hope the link works)  watch to at least 4 mins.

Скатывающая сила как измерить (youtube.com)  

Now pull on the stylus ... due to the compliance of the cartridge suspension  AND the headshell offset, the end of our extended cantilever will move downwards and to the left. If there was enough travel in the cartridges suspension and if we pulled on the stylus hard enough, the extended cantilever would ultimately touch the arms pivot point. 

So back to an actual cartridge... the action of stylus drag causes the cantilever to squat down a little. This has been talked about in other forums, and I believe mentioned by Michael Fremer,  but the action of stylus drag with an offset headshell also causes the cantilever to move to the right when viewed from the front of the cartridge. By how much? I don't know... would it be enough to cancel a carefully set up Lofgren alignment? Possibly. Would it cause an increase tracking error distortion? Maybe. 

Would it mean that a underhung arm, when playing a record actually has less tracking error distortion than an offset overhung arm? IOW opposite to what the theoretical static calculations would suggest. ..Maybe. 

If this 'yawing' action is a thing, it would be constantly changing with the level of modulation. I could speculate that it would result in a kind of "dirtiness" to the sound and a sense of the stylus scratching its way thru the groove. 

Cheers. 

Ok obviously that link didnt work...you may need to copy and past on the youtube search box 

lets try this Скатывающая сила как измерить (youtube.com)

As Lew points out, AS is set by the user at a constant magnitude.

Those who successfully opened the Youtube link I posted (the second one) will, I  suspect, be surprised at the significant variability of stylus drag, and at times, its "violence". Trying to negate the skating force that this creates with a constant magnitude counter force at the other end of the arm would seem to me to be an exercise in futility. How much stylus misalignment and hence distortion, stylus drag causes, is perhaps the key question along with what these nasty forces are doing to the cartridge's inner workings.