PedalPCB Referee EQ, clone of the Broughton Audio Resonant Filter Equalizer.

The Resonant Filter Equalizer creates unique tone control by combining a high pass filter, low pass filter, and middle equalizer. Both filters have their own resonance control, allowing a bump at the cutoff frequency, accentuating the effect of the filters. The semi-parametric middle eq includes a variable frequency control.

The resonance of the filters ranges from -3dB all the way up to +15dB. The -3dB setting is what you would expect from a standard, non-resonant filter. Adding resonance to the filters boosts the level of the cutoff frequency.

The filters have a slope of -12 dB/octave. The filters are the same in performance to the other standard Broughton filters, with the added ability of increasing resonance.

Some suggested uses:

Setting the HPF around 100 Hz with +5 dB of resonance, and a LPF set around 5k Hz can give a convincing cabinet sim. Add in the middle EQ for even more nuance. Experimenting with different frequencies and resonances can net a wide variety of speaker profiles.

Setting the HPF at the fundamental or first harmonic of your open E string (or B string) can make your low end tighter and more focused. Add resonance for more punch.

Setting the HPF to a lower frequency (30 to 60 Hz) with resonance can accentuate an octave down effect, while simultaneously removing unwanted sub frequencies.

Setting the LPF anywhere from 2k to 4k with added resonance provides an aggressive attack, giving more presence and character to your tone without having high end clank.

Setting the LPF at 10k with light resonance can give an airy Hi-Fi effect without having to boost all treble frequencies.

The input impedance is 1MΩ, and the output impedance is 100Ω.

If you have any questions, please message me!