General Equalization and Filtering Concept

General Equalization and Filtering Concept

           

              EQ or an equalizer is a vital tool in modern audio production.  Therefore, understanding the basic concept of general equalization and filtering has become very important to mixing engineers.  The followings are some basic knowledge of general equalization and filtering concept that the engineers must know.

An equalizer is a processor that is designed to change the tonal quality of audio passing through its process.   It operates by using a different numbers of filter circuits that have gain functions to audio signals of the specific frequency ranges.  The positive gain function is referred to “boost”, and the negative gain function is referred to “cut”. 

When we listen to sounds, louder always sound better, therefore, boosting frequencies will always sound better than cutting in the short run.  However, in the long run, cutting will create a more natural and cohesive sound. 

In addition, our ears are more sensitive to phase change during boosting and less sensitive when cutting.  Therefore, it is very important to apply as much cutting as possible instead of boosting, and in general, cuttings sound smoother than boostings.  Most of the time, cutting a specific frequency range will efficiently reduces a frequency masking and it will make the upper frequencies more apparent.

When boosting or cutting an audio signal, normally a wider Q or bandwidths are used in boost mode, while a narrower Q or bandwidths are used in cut mode.  Furthermore, sometimes instead of using a wider Q or bandwidths, using two narrower Q or bandwidths to distribute the load and focus on specific frequency ranges work better.

Lastly, when applying equalizer on a whole mix, the fundamental purpose should be to make sure that there is no excess or lack of frequency components throughout the frequency spectrum, and this is called, a “spectral management”.  In addition, using the solo function is only to help you identify some specific frequency component of a sound, therefore, always check the equalized sound within the mix.

Equalization always frustrates people, when they cannot feel the differences.  Always start with an extreme setting to identify the specific frequency range, then do the detail touch while listening the mix.  In addition, remember that when the frequencies are removed, it takes a moment for the brain to adjust.  Do not make an instant judgment.