The base with which an EQ works is the set of frequencies of a given sound, for example a guitar recording. The recorded sound, with all its frequencies, is the base we will work with. Obviously, the EQ can be used not only on recordings of isolated instruments, but also on songs or musical compositions, voice recordings, or any other sound we want to use.
The method of action of an EQ is to boost or cut certain isolated frequencies or an entire range of frequencies. For example, we can boost the 2000 Hz frequency, or we can boost frequencies from 1500 Hz to 2500 Hz. The result will be different and will fulfill the function we want for the sound to achieve a desired effect. In the following image we see that we have increased the frequencies around 250 Hz, we see that the EQ starts to act around 50 Hz and ends at approximately 1000 Hz.
On the other hand, in the following image we see that the EQ acts only on the 250 Hz frequency without affecting the surrounding frequencies. The same would apply to a frequency reduction (cut), the measure to increase or reduce frequencies is the Decibel (Db). In the previous graphs we see that the boost or increase was 15 Db.
Become an expert in equalization with the recommended book “ EQ in Music Production” (click on the image to go to the link):
