Filter Patches

SVF Module

The SVF module is an implementation of a state-variable filter algorithm described in Hal Chamberlin's book, "Musical Applications of Microprocessors." A unique feature of this filter object is that it produces lowpass, highpass, bandpass, and bandreject (notch) output simultaneously. Filtertypes: Lowpass Bandpass Highpass Notch The Cutoff Frequency and the Resonance can be controlled via CV1 / CV2.

Input: Input L, Input R, CV1, CV2 Output Signal 1, Signal 2

Spectral Module

Spectral Filter processes its input signal using a 1024-point FFT-based analysis/resynthesis algorithm that adjusts the level of each frequency band according to a graph you draw.

Input: Input L, Input R Output Signal 1, Signal 2

LP Gate Module

The LP Gate module is a combined VCA/Lowpass filter. Unlike a standard lowpass filter, it increases the cutoff frequency with the amplitude of the ingoing signal. The analog original of such a filter uses a vactrol to add an unusual, rubbery decay to otherwise fast modulation signals. This technique is often used to create melodic percussive tones (frequently referred to as "Bongos"). This effect has been simulated here, but with an adjustable decay response (the "VTime" control). The LPGate/VCA switches the filter from pure amplification to its amp/filter combination. Cutoff 20Hz - 8kHz Resonance 0 - 100% Offset and Resonance can be controlled via CV, the 'Ping' can be externally triggered.

Input Signal, Resonance, Offset, Ping Output Signal

Ladder Module

This is a classic Emulation of a Ladder lowpass filter. The most common filter in analogue synthesis is called theÂ low-pass filter and its name exactly describes its function: itÂ passes the part of the spectrum below its cut-off frequency,Â but attenuates or even removes those frequencies that lie aboveÂ the cut-off frequency.Â The most highly revered low-pass filter in analogue synthesisÂ was developed by Dr Robert Moog in the late 1960s. It firstÂ appeared in the modular Moog synthesisers of that decade,Â but its finest hour came in 1970 with the appearance of theÂ Minimoog. Largely because of its filter, this rather limitedÂ instrument has remained the standard by which all others areÂ measured, and has survived nearly 30 years with its reputationÂ intact as the most desirable of all integrated monophonicÂ synthesisers.Â Cutoff 20Hz - 8kHz Resonance 0 - 100% Cutoff and Resonance can be controlled via CV.

Input Signal, Cutoff, Q (Resonance) Output Signal

Formant Module

The Formant module is a vowel filter. Formants for English vowel sounds. Source: Music, Cognition and Computerized Sound, Perry R. Cook, ed., MIT Press 1999. Filtertypes: 1. "iii" (beet) 2. "eee" (bit) 3. "eea" (bet) 4. "aee" (bat) 5. "aae" (father) 6. "uuo" (book) 7. "ooo" (boot) 8. "oou" (but) 9. "iirr" (bird) 10. "aww" (bought) The slew parameter controls the transition sweep from one filter to another. The filtertypes can be switched via CV.

Input Signal, CV Output Signal

RED FILTER Module

The 'red' OSCiLLOT modules are designed for unconventional, noisy, distorted and somewhat surprising sounds. The RED FILTER provides 12 different filter types: Lowpass Highpass Bandpass Bandstop Resonant Allpass Gainlowpass Gainhighpass Gainbandpass Gainbandstop Gainresonant Gainallpass Cutoff and Resonance can be controlled via CV. A drive parameter will saturate and overdrive the input signal.

Input Signal, Cutoff, Q (Resonance) Output Signal

EQ	3 Module

The EQ 3 is a 3-Band parametric stereo Equalizer. Each band provides a gain attenuation/reduction of 12 dB. Band 1 has a frequency range of 10-100Hz Band 2 has a frequency range of 100Hz-3kHz Band 3 has a frequency range of 3kHz-23kHz The 'Q' factor (resonance) can be adjusted between 1-10 (10 = narrow)

Input Signal L, Signal R Output Signal L, Signal R

DIODE Module

This is a classic Emulation of a Diode ladder lowpass filter as found in Roland TB303 or EMS VCS3. Cutoff 20Hz - 8kHz Resonance 0 - 100% Cutoff and Resonance can be controlled via CV.

Input Signal, Cutoff, Q (Resonance) Output Signal

COMB Module

Use the Comb Module to apply the classic comb filtering effect to an audio input. A comb filter adds a delayed version of a signal to itself, causing constructive and destructive interference. The frequency response of a comb filter consists of a series of regularly spaced spikes, giving the appearance of a comb. Pitch 0-100 % (~Â 1-15.4ms) Feedback -1 +1 Pitch and Feedback can be controlled via CV.

Input Signal, CV1, CV2 Output Signal