Air bearing linear tracking arms can be made to have reasonably low moving mass, but, they lack the mechanical advantage of a fulcrum and pivot of a conventional arm, meaning that for any given effective mass, they do impose a lot more force on the cantilever to drag the arm to a new position than a conventional arm imposes in order to swing the arm around the pivot point. This is an issue even if friction is zero.
This is not the case with linear arms that employ a conventional pivot and a sensor that detects when the arm is out of linear position and then turns on a motor to move the entire arm assembly. But, as with every design, the motorized arm version has its own shortfalls, such as, vibration from the mechanism getting into the arm, lack of overall rigidity and mechanical grounding of tonearm vibrations).
The very short arm on some linear trackers (e.g., the ClearAudio arm), may give rise to another problem--a change in record thickness would mean a bigger change in VTA with a short arm than a longer arm.
The Schroeder LT is not a tonearm on a string design (I've helped set up and listened to a Schroeder arm-on-a-string and it is a good arm). It has conventional pivots, but also an innovative mechanism that moves the arm, including the pivot point, in a semi-circle to greatly reduce deviation from perfect tangency while not causing skating forces. Because it is using the drag of the arm tracking the groove to move the pivot, I don't know if it increases friction seen by the arm. The Reed T-5 uses a sensor to operate a motor to move the base of the arm to achieve the same kind of result as the Schroeder.
The bottom line is every type of arm has its pluses and minuses, and I haven't heard any type that I thought was obviously superior to another.
This is not the case with linear arms that employ a conventional pivot and a sensor that detects when the arm is out of linear position and then turns on a motor to move the entire arm assembly. But, as with every design, the motorized arm version has its own shortfalls, such as, vibration from the mechanism getting into the arm, lack of overall rigidity and mechanical grounding of tonearm vibrations).
The very short arm on some linear trackers (e.g., the ClearAudio arm), may give rise to another problem--a change in record thickness would mean a bigger change in VTA with a short arm than a longer arm.
The Schroeder LT is not a tonearm on a string design (I've helped set up and listened to a Schroeder arm-on-a-string and it is a good arm). It has conventional pivots, but also an innovative mechanism that moves the arm, including the pivot point, in a semi-circle to greatly reduce deviation from perfect tangency while not causing skating forces. Because it is using the drag of the arm tracking the groove to move the pivot, I don't know if it increases friction seen by the arm. The Reed T-5 uses a sensor to operate a motor to move the base of the arm to achieve the same kind of result as the Schroeder.
The bottom line is every type of arm has its pluses and minuses, and I haven't heard any type that I thought was obviously superior to another.