The filter node holds a very basic two pole filter(12dB/oct) it has multiple filter types supported by the Web Audio API with adjustable Gain Frequency and Q.
Filters can be chained in series to create a steeper rolloff filter so chaining 4 of them will create a classic 48dB/oct rolloff filter

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Filter Types

The possible filter types are the following:
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.