Curved and Straight Tonearms

Most DJ arms are "underhung" to aid in scratching, whereas straight tonearm with an offset headshell used for accurate audio replay are overhung. 

An S shape has the advantage of resonance reduction. The two bends add rigidity to vibration compared to a straight tube and flexural waves will be attenuated. Also a larger tube is more rigid than a small tube even if they weigh the same (tubes have good rigidity for their mass compared to a solid rod). Light weight straight tone arms have the increased risk of unwanted resonance due to standing resonance waves along the entire length.

Only advantage of straight is they are cheaper to build and can have lower mass for high compliance cartridges.

I have had both,  shoot,  I have both now.  Overall I agree with shadorne as far as curves contributing to resonance reduction and mass for high or low compliance cartridges.... Although,  I have heat shrinked and used interior dampening on light weight straight arms,  also with good results. 

Just thinking,  at one time,  I had my brothers Denon,  I believe that it was a DP60L... Might be wrong,  but I had it for about 2 months doing a few mods, 1 repair and some adjusting,  but this table had interchangeable arm tubes... a low mass straight arm and a medium mass s arm... both worked well.  At the time,  I didn't compare,  we exchanged them based on the cartridge. 

Why is it that most of today’s cost no object SOTA arms employ a straight arm tube. Where are the super "S" arms?