track through , gain stage “sweet spots,” معنی این دو تا عبارت چیه

Question

Apollo Twin features two Unison-enabled mic preamps, letting you track through exacting mic preamp emulations from Neve, SSL, API, Manley, and Universal Audio. An Apollo exclusive, Unison technology nails the tone of these sought-after tube and solid state mic pres — including their input impedance, gain stage “sweet spots,” and the component-level circuit behaviors of the original hardware.