What is an Audio Equalizer?
An Audio Equalizer is a device that can alter the amplitude of different frequencies of a recording to change how loud each frequency is. So an audio equalizer determines how much each frequency weighs in on a recording.
For example, say, we're playing music and we feel the bass is way too loud, with an equalizer, we can go to that bass frequency range and lower its volume, or amplitude, so that it isn't as loud. Vice versa, we can do the same for mid frequencies and high frequencies, either lowering or raising them. An equalizer gives us this possibility or opportunity so that the level each frequency contains is just right.
Below is an example of an equalizer's frequency controls.
You can see 60Hz, 125Hz, 250Hz, 500Hz, 1KHz, and it goes down the list. You can change the volume level from 0 to 15dB. So you can see visually now how an equalizer works.
An equalizer consists of one or or filters which can cut or boost the amplitude of frequencies in various ranges. The filters may be passive or active.
Equalizing may be done in hardware, as you see above, or in software with special audio software that allows it.
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