PATCH Mogger MuRf

Moogerfooger MuRF emulation. See www.moogmusic.com

built with Usine modules by Sylvain Thévenard.

MuRF stands for Multiple Resonance Filter Array. What this means is the MuRF has 8 filters and their levels are controlled by 8 sliders. It looks like a graphic eq, but the sound of the filters are very different: warm and resonant.

What is really unique is the ability to animate the levels of the 8 filters in up to 28 preset patterns. The rate of the patterns can be set by a knob, expression pedal, or plug a footswitch into the tap tempo input to match the rate to the tempo of your song. Rhythmic variations can be created by adjusting the levels of the filters. The Envelope control sets the shape of the modulation, which can be set for percolating techno rhythmic modulation or shimmering timbral morphing. Other controls include Input Drive, Output Level and Mix.

Settings

Drive

You can add drive to the input signal with to type of wave-shaper, from subtle crunch to hard distortion.

More Drive

Add a subsequent amount of drive.

Mix

Amount of processed signal. Sets the ratio of dry (signal as input) to wet (effected) signal.

Random

Randomizes all the parameters.

Filters Section

The MuRF contains 8 filters that can be configured for bass or mid-frequency voicing by the Bass/Mids switch on the front panel. In the Bass voicing, the lowest filter acts as a lowpass filter with a cutoff frequency of 110 Hz. The remaining seven filters are resonant filters with center frequencies of 160, 240, 350, 525, 775, 1200 and 1800 Hz. In the Mids voicing, all 8 filters act as resonant filters with center frequencies of 200, 300, 450, 675, 1000, 1500, 2200, and 3400 Hz.

Each filter has a slider that adjusts the gain of that filter. In this respect, the MuRF resembles a graphic equalizer. When a filter’s slider is all the way down, the gain for that filter is zero, and the filter’s output is zero. When the slider is all the way up, the filter’s output is at maximum. However the resemblance to a graphic EQ ends there.

The MurF’s filters have characteristics that set them far apart from a graphic equalizer. First, they are resonant filters. They boost the signal at the center frequencies of the filters. Second, they are tuned so they don’t overlap.

Follow Notes/Fixed

The 8 filters can be adjust with the frequency corresponding to the note played on the synthesizer. (allows only with the Poly Mini Mogg)

Bass

The first filter is adjust to the corresponding fundamental frequency and the other filters to the corresponding frequency to keep the frequency voicing of the original MuRF. For a A4, which fundamental is 440 Hz, the first filter is adjust to 110Hz. For a D5, which fundamental is 587 Hz, the first filter is adjust to 147 Hz For a G2, which fundamental is 98 Hz, the first filter is adjust to 98 Hz

Mids

This is the same as above but not glue to corresponding fundamental frequency. For a A4, the first filter is adjust to 200 Hz, like the original MurF, for Bb4, it is pitch by semi-tone,etc.

Sliders (x8)

Can be manipulated manually, or being Animated. The Free/Animated switch sets the animation on or off.

Resonance

Changes the way the filter sounds. Or, in technical words, it changes the shape of the frequency response.

When Resonance is near 0 the low overtones come through evenly. When Resonance is turned up to around 7, the overtones near cutoff will be boosted, creating a whistle-like or vowel-like quality. When resonance is above 8, the filter actually produces its own tone at the cutoff frequency.

LFO Section

The filter center frequencies can be modulated by the LFO section.

Rate

Sets the frequency of modulation

Amount

Sets the overall amount of modulation of the filter center frequencies by the LFO

Square/Sine

The LFO provides six waveforms : triangle, sine, square, saw, saw invert and random.

The Envelope Generator

In the MurF, there are 8 Envelope generators, one for each filter, that shape the Volume of that Filter’s signal. The shapes of the Envelopes are all determined by the setting of the Attack, Hold and Release knob.

The patterns

Selected by the PATTERN combox in the MuRF's settings. There are a total of 28 patterns preloaded. You can easily create your own.

Sequencers and Pattern Generation

The MurF’s Animation contains a simple 8-channel sequencer, one channel for each filter, each capable of triggering an Envelope Generator that shapes the volume of the filter. For each step, on each channel of a pattern, the corresponding filter’s envelope can be triggered, or paused. The envelope control morphs through different envelope shapes as you turn it, creating effects that are highly rhythmic in nature, or are swirling and ethereal.

Speed

Sets the speed of the pattern. The Speed can be linked to the DAW's Tempo. (see MuRF's settings)

See also

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