So what is an EQ anyway? EQ stands for "equalization." Simply put, and EQ is a fader. That’s the easiest way to remember it. Just like a normal fader on a soundboard, it is used to equalize the sound relative to something else. Instead of turning the volume up or down on the entire track, the purpose of EQ is to adjust the volume of different frequencies inside of that track, equalizing it to its self.
So Let’s talk frequency for a second. The human ear generally hears frequencies between 20Hz and ~16kHz (kilohertz), depending on how old you are, and how many rock concerts you attended. As the number of Hz gets higher, the frequency also gets higher pitched.
To understand frequency a bit more, we can categorize frequency into three main sections: Bass, Mids, and Treble. The bass region is between 20Hz and, say 200. The mid frequency region covers the largest area, from 200 Hz to around 5kHz depending on who you ask. The treble is everything above 5kHz, all the way up to 16kHz.