> ## Documentation Index
> Fetch the complete documentation index at: https://amethyst.geoxor.moe/llms.txt
> Use this file to discover all available pages before exploring further.

# Filter node

The filter node holds a very basic two pole [filter](https://en.wikipedia.org/wiki/Filter_\(signal_processing\))`(12dB/oct)` it has multiple [filter types](https://developer.mozilla.org/en-US/docs/Web/API/BiquadFilterNode/type) supported by the [Web Audio API](https://developer.mozilla.org/en-US/docs/Web/API/Web_Audio_API) with adjustable [`Gain`](https://en.wikipedia.org/wiki/Gain_\(electronics\)) [`Frequency`](https://en.wikipedia.org/wiki/Frequency) and [`Q`](https://en.wikipedia.org/wiki/Q_factor).

<Tip>
  Filters can be chained in [series](https://en.wikipedia.org/wiki/Daisy_chain_\(electrical_engineering\)) to create a steeper [rolloff](https://en.wikipedia.org/wiki/Roll-off) filter so chaining 4 of them will create a classic `48dB/oct` rolloff filter
</Tip>

## Filter Types

The possible [filter types](https://developer.mozilla.org/en-US/docs/Web/API/BiquadFilterNode/type) are the following:

* `highshelf`
* `lowshelf`
* `peaking (bell)`
* [`bandpass (band)`](https://en.wikipedia.org/wiki/Band-pass_filter)
* [`highpass (lowcut)`](https://en.wikipedia.org/wiki/High-pass_filter)
* [`lowpass (highcut)` ](https://en.wikipedia.org/wiki/Low-pass_filter)

<Warning>
  The Q and/or Gain may not have an affect with certain types, and/or certain filters require a Q value of `+1` to work as expected.
</Warning>