There are only three elements to sound (phase, frequency and amplitude) and time coherence is smack dab in the middle of the phase element. This Blog's objective is to impart the quintessential importance of accurately dialing in the vertical tracking force of your cartridge which will enhance your listening experience by increasing coherency.
Coherency is defined as: logical and orderly and consistent relation of parts. If you have not accurately dialed in your VTF, you can still experience all the individual sounds in the right volume proportion with excellent attack and decay. However, it will sound as though there isn't a musical whole but rather many separate musical parts occurring more or less simultaneously and inexorably deprived of audio coherency.
This lack of coherency mitigates fooling the brain into thinking that you are listening to the real thing. When it is right, you simply forget that you are listening to the components of your system which allows you to relax and emotionally connect with the recorded event. This audio coherence provides greater focus giving instruments and vocals a higher level of delineation and more air around them in addition to longer decays. Pace, rhythm, attack, and timing are ameliorated portraying a more natural, involving realistic musical whole. The caveat: tiny changes can have quite dramatic effects on the sound, so proceed slowly and be prepared to work backward and forward around a mean point. I would recommend the VPI digital stylus force gauge from Bob's Devices Stylus Force Gauge to accomplish this task.
This begs the question why should VTF have such a dramatic impact on a system's musical performance? Although it’s impossible to be sure, my thinking is that it’s a function of the generator itself. As you adjust VTF you alter the cartridge-ride height and thus the angle of the cantilever. This in turn alters the relationship between the magnet and the coils around it -- or the opposite in the case of a moving-coil cartridge. Either way, the nearer the moving element is to the neutral position the more superior the musical presentation. Move it away from that point and both the suspension compression and the electromagnetic interaction will start to vary, damping the movement and altering the peak value of the signal generated. Get the moving element as near to the neutral position as possible and you afford it the ultimate freedom to react and the widest range of reaction -- which is exactly what it sounds like when you get the VTF spot on.