While the Acuscope’s Frequency and Intensity settings control the delivery of the treatment carrier waves, the Gain Spectrum presets the monitoring level, “fine-tuning” the biofeedback for accuracy and precision.  The “optic eye” of the Gain Spectrum is how the circuitry “looks” at the tissue.  Sensitively adjusting the Gain to where the focus is within range allows the instrument to “see” cellular issues more clearly.
The Gain required to produce auditory and corresponding numerical readouts is telling us just how impeded is the flow of current moving through the tissue between the electrodes.  The higher the Gain setting necessary, the more resistance there is.  As the Gain is changed, the viewing window is being adjusted.  As the treatment improves tissue conductivity, the Gain can be lowered.
The choice of frequencies to be applied is determined by the needs of the tissue currently between the electrodes. Adjusting the Gain, we look at the numbers and listen to the corresponding sounds. Interpreting the feedback, we can apply appropriate frequencies to optimize outcomes.  The resolution capability is in the programming. We can either assist or compromise its perception by our utilization of the Gain.