How to use an EQ as a channel insert on an audio console - Stage Left Audio
EQ Basics: Part 1 of 3 (EQ Channel Insert)
Placing an EQ as an insert to a channel on a console provides greater EQ control over the source. It works great as a replacement for the factory board channel EQ; however, a low quality EQ may introduce noise into the channel.
Care must be made when setting EQ levels.
The trick to good sound...? Don't overuse the EQ. When correcting sound quality issues, start with the source first and then make your way back to the EQ.