“BPB Dirty Filter is a freeware tube distortion effect. It features a pair of resonant filters that can distort a specific area of the frequency spectrum.
In a way, BPB Dirty Filter is similar to multi-band distortion but with a more straightforward workflow. Choose a frequency that you’d like to distort and increase the Drive parameter to add resonance and tube saturation.
With the Drive knob set to zero, BPB Dirty Filter operates as a transparent filter plugin. In this mode, it is great for cleaning up low-frequency hum or removing high-frequency noise.
When the Drive knob is set above 50, BPB Dirty Filter transforms into a powerful distortion effect. Use high amounts of distortion in tandem with the Mix knob to keep some of the original audio.
- High-pass filter (20 Hz – 20 kHz).
- Low-pass filter (20 Hz – 20 kHz).
- Adjustable slope (12, 24, 36, or 48 dB/octave).
- Tube distortion.
- Mix (0 – 100%).
- Output volume (±12 dB).
- Available for Windows & macOS.
- 32-bit & 64-bit compatible.
- VST2/VST3/AU/AAX plugin formats.”
Source : bedroomproducersblog.com