An equalizer (commonly and simply known as EQ) is a device that allows the user to adjust the level of specific frequency ranges within an audio signal. It typically consists of frequency bands, with controls that allow the user to boost or cut the level of each band. On OS, the EQ that's used is known as a graphic EQ. This EQ has 3 bands. The low-frequency band is responsible for adjusting the bass frequencies, the mid-frequency band adjusts the midrange, and the high-frequency band adjusts the treble. Using an EQ, it is possible to shape the tonal characteristics of an audio signal by boosting or cutting specific frequency ranges. This can be useful for a variety of purposes, including correcting for imbalances in the frequency response of a system or sculpting the tone of an instrument or vocal. It is at the bottom of the advanced tools section.