An equalizer is a unit that equalizes or compensates for
different tonal side effects and places them in synchronization. In this way,
the equalizer changes the quality of the audio tone that passes through it.
Equalizers use various filters and allow you to adjust, or gain, the frequency
ranges of the audio signals. These adjustments can be positive gains called
"boosts," or negative gains called "cuts."
Here's a list of the common types of filters found in
equalizers:
High and Low Pass Filters These are the most
commonly used filters. A high-pass filter, also called a low-cut filter, lowers
the sound level below the user selected cutoff frequency. The low-pass filter,
also called a high-cut filter, lowers the sound level above any user selected
cutoff frequency.
Shelving Filter The shelving filter applies the
same gain change, or adjustment, to all frequency sounds above the user
selected frequency.
Peaking Filters The peaking filter is used only
for special applications. It offers fine overall tone adjustments when you must
reach a specific frequency
Here's a list of some types of equalizers:
Shelving Filter Equalizer The shelving filter
equalizer is the simplest and most commonly used equalizer. It has one dial to
control the bass and another dial to control the treble.
Parametric Equalizer A parametric equalizer
allows you to control the cut and the boost, as well as what frequency is most
affected.
Graphic Equalizer The graphic equalizer takes
the guesswork out of equalizing. These equalizers have a graph (hence the name
graphic), on which you can see all the possible frequencies. You can make
precise adjustments because you're not relying on your hearing to make the
adjustments, but can actually make the adjustments according to what you see on
the graph