"S" shaped tonearm ?

One can get the proper geometry by just bending the head of the arm (like most tonearms), so that is not the reason for the S-shaped arm. I believe that the S-shape is an attempt to balance the mass of the arm about the axis drawn between the pivot and the stylus. Without the S-shape there is more mass on the "outside" of this axis. Why such static balance along that axis is important is not clear to me (aside from reducing torque in one direction at the pivot). The "cost" of such design is much more mass. For any given mass, other designers would favor increasing the rigidity of the arm instead of trying to achieve such balance.

I think it was a combination of improved geometry and "sexiness" of the s-shaped arm. It was a way to stand out from many other mass market products (which of course got picked up by the mass marketers). Just MO.

The S shape arm is an inferior design.

It has been mathematically proven that the minimum tracking error of a pivoted arm is given by the Baerwald equations, which require a headshell offset angle.

There are 2 obvious ways to obtain a headshell offset angle:
1. Angle the headshell relative to the armtube
2. Bend the armtube into an "S".

In the field of Strength of Materials, which is the study of shapes and their response to stress (and has nothing to do with actual materials, so the name can be misleading to non-engineers), it is mathematically proven, and experiements back this up, that the deflection of a column is proportional to its length given other equal parameters. In Vibrational Analysis it is proven that longer beams of the same cross sectional area will suffer far greater vibrational deflection. Therefore, in both the static and dynamic conditions, a shorter armtube would be superior if one's goal is neutrality.

Since the S shaped armtube is inferior in both strength and vibrational analysis, with no other advantages, there is simply no reason to do this other than reasons of aesthetics, ease of fabrication, or nostalgia.

Anyone making a case for an "S" shaped armtube being superior is showing that either he has no technical understanding of the matters at hand or does not have a goal of neutrality for the tonearm.

The current "high end" tonearms i.e. Schroeder, Graham etc. are all straight and relatively short arms.

The genesis of "S", and for that matter "J", shaped arms is probably buried in the mists of time, though I think that Larryi has a pretty plausable explanation. The only reason that I can see to currently design one of these arms is that it becomes compatible with universal headshells, which are absolutely necessary in the DJ world and pretty convenient in the audiophile world, though as Bill stated, there will be a high sonic price to pay for such convenience. As always, sigh!

I always thought that S shaped arms started disappearing around the time MCs became the rage and that it was discovered that you needed a more rigid arm tube for MCs than with light and compliant MM or moving iron designs, so that extra material to make it stiffer and extra material to keep the S shape just wouldn’t do.

I remember the SME model that was S shaped with a titanium wand and I think it was no slouch teamed with a compatible cart.

I like the way you seem to think that everything made now is better than everything made then. I guess one does fall into that trap when one is a monger.