In simple words or in a layman’s word it may be referred to as tone controls, and in more technical words a graphic equalizer system may be defined as a device which is used for processing an audio information which may be typically in the form of varying frequency such that it may be trimmed to pass a certain band of frequency while blocking a certain bands of frequency as per the user setting and choice.
Now you may wonder, what are these so called bands of frequencies embedded inside a music content or audio information? Well as we all
Quite similarly, in electronic equipment, particular music information is composed of many different frequencies corresponding to the different vocals present, such as sound from a guitar, drum, voice etc.
A graphic equalizer is a circuit which is responsible for neutralizing a certain spectrum of frequencies, allowing a certain spectrum of frequencies for getting amplified into the connected loudspeakers.
The most basic form of a graphic equalizer is a bass/treble control which may be considered very basic because the pair is associated broadly for processing frequencies from 30 to 1000 Hz (for bass control) and around 1000 to 20,000 Hz (for treble control).
Want to further know, how to build a 10-band graphic equalizer circuit at home, see the below given link: