Originally Posted by Class A
Description of the tonearm is a static balance. What does that mean? The Headshell on this arm is made of very light magnesium metal. Very easy to work with.
A good headshell should be super rigid and inflexible yet super light weight. Its job is to hold the stylus in the exact correct position, so it can do its job accurately, rather than bend or contort when lateral or vertical forces are applied to it such as record warps or other anomalies. Even tiny microscopic flexes or bends can cause audible distortions in the playback. The actual material they use is less important than how well they designed it.
First a quick refresher course on levers, which is what a tonearm is:
I can't guarantee what they mean by "static", because some companies vary, but generally speaking the tracking force, the downward push into the grooves, is applied with one of the following:
A. electromagnetic force (an electromagnet)
B. a spring
C. a slightly skewed balance where rather than placing the fulcrum (the pivot point) where there is neither an upwards nor downwards force [so the arm sort of floats around freely as if it is in outer space and experiencing zero gravity] instead one side has more weight than the other, so that heavier side pushes downward into the grooves.
"C" is generally the most common.
Static balance (usually) means C, and that by moving the counter weight forwards or backward you can achieve a point where there is no downwards force nor upwards force. Sort of like having two identical twins [of identical weight] on a child's seesaw. But if you give one of the twins a bowling ball to hold they will then swing the seesaw so they push towards the ground. [The ground in this scenario is the record grooves, of course.] This is the "tracking force" used by most companies.
Here's a visual slide from my AR-XA turntable video (which got slightly modified once it hit the video), explaining why the best
kind of static balance is not "unstable", nor "stable" (common in tonearms), but rather neutral
What makes starting off with a neutral balance arm better [before the tracking force is then applied to one side so it sinks into the grooves] is if the arm rises or falls due to a surface warp (bumps/dips) the tracking force does not vary at all, whereas with the more common "stable" balance method used by others it will alter the force depending on where the lever is, up high off the record surface or down closer to it.
A side benefit of neutral balanced tonearms is the tracking force also does not vary if you move the turntable to a new shelf which is on a tilted surface, whereas with the more common stable balance variety you need to re-calibrate the tone arm tacking force every
time you move your turntable to a new, less than perfectly level shelf.