GBand is a band-pass filter. It removes frequencies from the input that are above or below the specified cut-off points.
GBand uses a high- and a low-pass filter in series to remove the unwanted frequencies. It is equivalent to using GHi and GLow, one after the other.
Band-pass filters are useful during mixing to remove unnecessary frequencies from a track. A track that sounds fine on its own can sometimes be difficult to fit into a mix. Narrowing its frequency range will often help.
Resonance boosts the volume of frequencies around the cut-off points. This can create large peaks in the output. Because of this, the GUI features a peak display showing the maximum peak output level. The peak display is reset by clicking on it.