4 Band Parametric EQ (fil4.lv2)

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4 Band Parametric EQ (fil4.lv2) is a graphical EQ with High/Low shelfs and High/Low Pass filters which is based on DSP from Fons Adriaensen's highly regarded fil-plugin. It is available in both mono and stereo variants and has a spectrum display plus waterfall FFT history built-in. The display also has vertical zoom and the window can be resized.

There is also a standalone JACK client of the plugin available. fil4.lv2 is part of x42-plugins by Robin Gareus.

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Here's a video overview for anyone that's interested: https://www.youtube.com/watch?v=2kbHPL_9Kyw