Eq Filter

Frequency Knob Sets the filter’s center frequency.
FM Input Linear audio-rate FM modulation input, with FM depth knob.
Q Knob Sets the quality factor, or resonance.
Gain Knob Sets the equalizer band level (-30 dB to +30 dB).
Filter Selector Choose between low-shelf, peaking or high-shelf equalizer filter.
Output Trim Knob Output level adjustment.
Inputs Signal to be filtered (stereo).
Outputs Filtered signal (stereo).

Overview ⚓︎

The Eq Filter is a one-band equalizer that can work in low-shelf, peaking or high-shelf mode.

It supports both mono and stereo processing. For mono processing, use the left input and output jacks.

You can use a single Eq Filter to highlight or tone down part of the spectrum, or chain as many as needed to build a multi-band equalizer.

Equalizers have three main parameters: frequency, Q and gain.

Frequency sets the center frequency for the given filter type. See Filter Types for more information about what this means for each filter type.
Gain adjusts the equalizer effect depth. Positive gain will boost frequencies, while negative gain will attenuate them. When centered, the filter will have no effect.
For the peaking equalizer, Q controls the precision of the filter. A filter with a higher Q will impact a narrower frequency band.
For low-shelf and high-shelf filters, raising the Q factor will make the transition between the two frequency bands steeper. It will also boost the frequencies near the cutoff frequency on the louder side, and attenuate them on the softer side.

In Depth ⚓︎

Gain ⚓︎

Most equalizers will go to +12 dB, or sometimes +20 dB. This one goes up to +30 dB. This is way too much in most situations, but can be handy when you really need it.

Setting too much gain on a signal that’s already loud in the affected frequency band will make the filter clip internally. If your patch sounds scratchy or distorted, make sure the equalizer gain hasn’t accidentally been set too high.

Filter Types ⚓︎

Low-shelf

A low-shelf filter will boost or attenuate frequencies below the Frequency knob setting. Frequencies above that will be unaffected.

Low-shelf filter attenuating frequencies below 800 Hz by -6 dB

High-shelf

A high-shelf filter will boost or attenuate frequencies above the Frequency knob setting. Frequencies below that will be unaffected. The effect depth is set by the Gain knob.

High-shelf filter attenuating frequencies above 800 Hz by -6 dB

Peaking

A peaking equalizer boosts or attenuates frequencies around the Frequency knob setting. Frequencies far from the center will be unaffected. The width of the boosted or attenuated frequency band can be adjusted with the Q knob. A higher Q means a narrower band.

Peaking equalizer attenuating frequencies around 800 Hz by -6 dB

FM ⚓︎

The filter supports linear frequency modulation through the FM input. Use the attenuator to adjust the FM depth.