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Basics:

Choose the filter type, lowpass, highpass, or bandpass, using the radiobutton. The "cutoff" knob controls the base frequency of the filter, and the "res" knob controls the resonance, or emphasis boost at that frequency. The overall gain of the device is controlled using the "gain" knob. The devie can be enabled and disabled using the "enable" button. When receiving an input signal on In1 only, click on the "mono in" button to copy the Out1 signal to Out2.

Ring Modulator:

The ring modulator adds a sine-wave ring modulation to the signal. Set the frequency of the ringing using the "freq" knob.

Bypass this unit by clicking the green light under the word "mod" - this completely removes the ring mod from the signal chain.

Distortion:

The distortion unit adds a rich distortion to the signal. When the "post" button is red, the distortion is added at the end of the signal chain, just before the outputs. This can add brightness to the filtered signal. When the "post" button is not pressed, the distortion will the distort the input signal before it is passed into the filter, thereby producing a warmer, more distant distortion.

Bypass this unit by clicking the green light under the word "distortion" - this completely removes the distortion from the signal chain.

MIDI:

Choose the MIDI channel using the MIDI channel selector in the lower right corner of the interface. The MIDI activity light will flash red when receiving MIDI data.

Refer to your Pulsar/Scope manual for guidance on assigning MIDI controllers to Z Filter's knobs.

Cutoff Frequency Modulation:

There are three sections, detailed below, for modulating the cutoff frequency, each with its own bypass and depth controls. These, in combination, can modulate the filter in interesting and surprising ways. The base frequency is set with the "cutoff" knob, and the modulation sources will combine to modify this. You can also add to the cutoff frequency modulation manually by turning the "cutoff" knob with the mouse, or from an external MIDI controller (e.g. your keyboard modwheel).

Envelope follower:

The envelope follower tracks the amplitude of the input signal (stereo channels are summed before feeding the follower), and uses the resulting control signal to modulate the filter's cutoff frequency.

The "snap" knob, when increased, makes this modulation signal follow the amplitude contour of the the audio more tightly. When decreased, the follower will be more loose. To hear this clearly, choose a lowpass filter with very high resonance, and the follower set to maximum depth. Now adjust the snap knob, and listen to the resulting filter changes over time.

Env Trigger:

The envelope trigger is an ADSR envelope which modulates the cutoff frequency. The envelope is triggered by incoming MIDI note events. Its depth can be made velocity sensitive by using the "velocity" knob.

LFO:

The low frequency oscillator modulates the cutoff frequency. The shape of the LFO can be chosen by clicking on the radio button - choices are Sine, Square, Forward Saw, Reverse Saw and Random. The speed of the oscillation is determined either by the "speed" knob, or if the sync button is pressed, by the incoming MIDI clock signal, as divided by the sync divider selection. To change the sync division, click on the sync division text and drag up or down. When the division selection is 8, the LFO will cycle once every 8th note, at the tempo of the current MIDI clock. When it is 4, it will cycle every quarter note. etc.