The AE400 is an advanced active equalizer suitable for music production, post production, and live sound. The AE400 is made up of 4 bands of fixed and active equalization. Each band is completely overlapping with all other bands and has its own Q (bandwidth), fixed gain, and active gain controls. A key filter for each band allows the active gain response to be as selective or broad as needed, based on the Q (bandwidth) control. Each band can use the input signal or selected side chain signal to trigger the active EQ response.