# Equalizer
A simple [Parametric Equalizer](https://en.wikipedia.org/wiki/Equalization_\(audio\)#Parametric_equalizer).
## Graph
* **X axis:** shows frequencies from 20 Hz to 20,000 Hz, divided into [octaves](https://en.wikipedia.org/wiki/Octave_\(electronics\)) (this makes the X axis appear nonlinear).
* **Y axis:** shows amplitude from -18 dB to 18 dB (displayed linearly with respect to decibels).
* **Analyze:**
* **In** **(Button):** toggle display of input signal on graph (before signal alterations)
* **Out** **(Button):** toggle display of output signal on graph (after signal alterations)
{% hint style="info" %}
The bubbles on the graph can be used to plot *Cutoff frequency\** and *Gain\*.* Using the scroll wheel on these filters will alter their *Bandwidth/Resonance\*.*\
\
\*These terms are explained in the *Filter Settings* subsection of this page.
{% endhint %}
## Filters
You'll notice that there are 8 columns with numbers 1-8, these represent 8 different filters (of 5 filter *types*) that can be used to alter the input signal.
### Filter Settings
* 
**:** toggles their respective filters on/off. (Notice the symbols next to the numbers)
* 
**:** adjusts slope of **Highpass (1)** and **Lowpass (8)** Filters, respective to each filter.
* 
**:** adjusts gain of **Filters 2 through 7**, respective to each Filter.
* **Row of Knobs:**
* **Top Row:** adjusts the Cutoff Frequency of their respective filter
* **Bottom Row:** adjusts the Resonance (**Filters 1**, **2**, **7**, and **8**) and Bandwidth (**Filters 3**, **4**, **5**, and **6**) of their respective filters.
### Filter Types
* **1:** This is a **Highpass Filter**, it *removes* frequencies *below* the cutoff frequency.
* **2:** This is **Low Shelf Filter**, it can either *boost or reduce* frequencies *below* the cutoff frequency.
* **3 through 6:** These are **Peak Filters**, they can either *boost or reduce* frequencies **around** the cutoff frequency.
* **7:** This is a **High Shelf Filter**, it can either *boost or reduce* frequencies *above* the cutoff frequency.
* **8:** This is a **Lowpass Filter**, it *removes* frequencies *above* the cutoff frequency.
## Other
* **In (Slider):** adjusts the gain of the input signal.
* **Out (Slider):** adjusts the gain of the output signal.
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