Are linear tracking arms better than pivoted arms?

Thanks Phil,
My Souther has been a stable, unfussy (after a very fussy set up), reliable tool, perched atop my SOTA Star for a decade. I does require cleaning on occasion (a five minute task) and must be absolutely level. My arm/turntable combination produces so little "grove rush" that on a good quality recording one has to look to see if a record or a CD is playing. Most of us do not live in a cost is no object world. I am grateful to designers like Lou Souther, who make products that give ordinary folks a glimpse of the best for a modest price.

I have owned several linear tracking arms.

Air bearings don't work. I am sure all of you have noticed that the more pressure you put in the arm, the better it sounds. The problem is that there is a violation of a fundamental turntable design rule, which is this: for proper LP playback, there can be no bearing slop between the surface of the platter and the cantilever of the cartridge.

Air bearings by definition have bearing slop, and this is why they sound better as you add more pressure.

The other problem, already mentioned, is that due to the excessive lateral tracking mass, it is the cantilever of the cartridge that defines the tracking error **not the arm**! This is because the cantilever has to flex to move all that mass.

The result is that a good quality arm like a Triplanar or Phantom has lower tracking error than any air-bearing arm!

In order for a straight-tracker to actually do its job right, it cannot have any slop in any of its bearings. Linear tracks do exist that have no slop, so it would not be that hard to devise an arm that also has no slop, using a servo not unlike what the old Rabcos used (updated of course). Arms like that don't exist right now so for the time being, radial tracking arms rule the State of the Art roost.

Ralph, I suspect some of us currently using the Walker Audio
table and air bearing arm may disagree with you: no slop,
exceptional tracking, marvelous resolution and outstandingly
articulate bass reproduction. And, yes, I do very much like
and admire the Triplanar arm.

Overall, way too many generalizations in this thread, folks.
Albert got this right in his comments near the beginning, imo.
.

"Air bearings don't work" is quite a generalization. While I have only compared my Trans-Fi Pro to Graham 1.5tc & SME IV, I have no doubt that the Pro handily surpasses both of these pivot arms. To AtmaSphere's point, the Pro operates by design on low air pressure. A high-pressure bearing may propagate increased turbulence and vibration. This theoretical disadvantage may in turn off-set any theoretical advantage in tracking. Of course it is all about execution.

The Trans-Fi also allows shortening of arm wand length down to 1". While one can debate the theoretical advantage of a short wand, IME the audible improvement is easily detected down to the last 1/4" of adjustment. While a short wand may be considered an ancillary feature of a linear design, this feature is of great sonic significance and is obviously unavailable in a pivot arm.

Bravo Phil! What a well written post.