The "science" behind counterbalancing...
To illustrate the issue as it pertains to the "nose-heaviness" of the Equinox, we need to think back to the ideas of levers and fulcrums and leverage that were taught in high-school physics class, or even just picture the grade-school playground's see-saw/teeter-totter. As we know from science class, the situation with a metal detector is that we are placing a relatively large amount of "mass" (the coil) at the end of a long "lever" (the shaft). Therefore, the coil is essentially "using leverage to its advantage," so to speak -- with gravity acting on the coil so as to exert a multiplied downward force at the end of the shaft. And therein lies the issue. In order to keep the detector from resting in a fully vertical position (coil down, butt-end of the shaft up), due to the "downward" force applied by gravity to the coil, an equal but opposite force must be applied. So, how is that "counter-force" applied? Well, in terms of the Equinox -- a machine with virtually ZERO weight at the "butt-end" of the shaft, the detectorist must supply ALL of that "counter-force" needed, in order to keep the detector swinging in proper "detecting position." In other words, the detectorist must exert enough counter-force, with their wrist/arm/shoulder muscles, to counteract the "leverage" of the coil's downward force being exerted out at the end of the shaft. THIS is why the Equinox feels so "nose-heavy", and why counteracting that nose-heaviness causes discomfort for many users. And, again, thinking about the "fulcrum" and "lever" concepts, applying a counter-force AT THE HANDLE of the machine (i.e. at the "fulcrum,") means that the detectorist is not able to take advantage of the "leverage" idea, when applying this "counteracting" force. The ONLY way leverage could be utilized, would be if there were some force (i.e. weight) BEYOND the handle, near the butt-end of the shaft, acting to oppose the downward force of the coil. It is HERE, that the idea of "counterweighting" therefore enters the picture, to solve this dilemma.
