All-Pass Filters are so named because they do not affect frequency response. Instead, they affect signal phase only and, therefore, can be used to compensate for the phase anomalies caused by normal equalization filters. All-Pass Filters are available with up to sixteen bands.
Active Band selects the current band to be adjusted. Center Freq. adjusts the center frequency for the current band. Bandwidth adjusts the range of frequencies, above & below the center frequency, which are also affected by the current band. These settings may also be adjusted by dragging the band controls shown inside the graph. Dragging the white dot affects Center Freq. Dragging either yellow dot affects Bandwidth. Add Band & Remove Band work within the designated number of bands for the filter. Bypass Band & Bypass All disable the band(s) without changing settings. Drag Points turns on/off the band controls, revealing the resultant curve only. Band highlights the phase response of the current band inside the graph.
See Transfer Function as an effective diagnostic tool to be used in conjunction with All-Pass Filters.
Right-clicking over certain settings will provide a menu of additional options.