Understanding and Using
Your moogerfooger®
MF-105 MuRF™
TABLE OF CONTENTS |
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Getting Started............................................ |
3 |
Frequencies and Filters............................... |
5 |
The MuRF’s Filters..................................... |
7 |
EnvelopeGenerators................................. |
10 |
Sequencers and Pattern Generation.......... |
11 |
The MuRF’s Animation............................ |
11 |
The MuRF’s Tap/Step Input..................... |
13 |
Audio Level Controls and Mixing............ |
14 |
Using Both Outputs Together.................. |
14 |
Expression Pedals and Voltage Control.... |
15 |
Some Typical Setups................................. |
16 |
Technical Information............................... |
17 |
Limited Warranty...................................... |
19 |
MF-105 Specifications............................. |
20 |
Appendix A - the MuRF’s Patterns........... |
22 |
Welcome to the world of moogerfooger® Analog Effects Modules! Your model MF-105 MuRF is a rugged, professionalquality instrument, designed to be equally at home on stage or in the studio. Its great sound and jaw-dropping effects come from the state-of-the-art analog circuitry, designed and built under Bob Moog’s personal direction.
Your MuRF is a direct descendent of the original Moog™ modular synthesizers and professional rack effects. It contains two basic functions: an 8-band array of resonant bandpass filters, and a pre-programmed “Animation” module that generates sequences of envelopes that modulate the levels of the 8 filters. Several of the performance parameters are voltage-controllable, which means that you can use expression pedals, MIDI-to-CV converter, or any other source of control voltages, such as other moogerfoogers, to ‘play’your MuRF.
While you can use it on the floor as a conventional effects box, your MuRF is much more versatile and its sound quality is higher than the single fixed-function “stomp boxes” that you’re probably accustomed to. The MuRF is an astoundingly versatile effects device, you will find it provides an incredible variety of effects. You will find that your MuRF is a deep musical resource and will become your creative companion as you explore its possibilities.
The following pages will first tell you how to hook up your MuRF and set the panel controls for the ‘basic’setup. Next, we’ll explain how the functions of your MuRF work. After that we’ll go through the panel features and give you suggestions on how to use your MuRF in specific applications. At the end of this booklet you’ll find technical specifications, service and warranty information, information about Moog Music and diagrams of the MuRF’s Animation patterns.
GETTING STARTED
Here are some simple instructions on how to quickly plug in and try out your MF-105.
1.Unpack your MF-105. Place it on a table while you become familiar with its features.
2.Check that the power adaptor has a nominal rating of +9 volts, providing at least 300 mA (milliamperes) of current and is also rated at your country’s standard power voltage (120 volts A.C. for the United States and Canada; 100 volts A.C. for Japan; and 220 volts A.C. for most other countries). Plug the power adaptor’s cord into the MF-105’s ‘+9V’jack. Then plug the power adaptor itself into a power voltage receptacle. Note the MuRF uses a different power supply than other moogerfoogers, which is only rated at 200mA. Using a 200mA moogerfooger power supply may result in hum, distortion, and other less than desirable audio artifacts. Make sure to use the proper power supply.
3.Note that the BYPASS light is on. It will light up either red or
green. Red indicates that the MF-105’s effect is off-line (bypassed), while green indicates that
the effect is on. Pressing the ‘stomp switch’will toggle the BYPASS light between red and green. For now, leave the BYPASS light on red.
Refer to Figure 1 for steps 4. and 5.
Figure 1 - Basic Connections to MuRF
4.Connect an instrument cable from the LEFT/MONO jack to a line-level input on your amp or mixer. Turn the volume control on your amp down but not off.
5.Connect an instrument cable from your signal source to the AUDIO IN jack. You can feed virtually any instrument-level or line-level signal through your MF-105. Examples are guitar, bass, keyboard, theremin, drum machine, or Effects Send output on your mixer. Play your instrument (or turn on the signal source). Adjust the volume control on your monitor amp so that the sound level is comfortable.
6. Now set the MF-105 panel controls as follows (See Figure 2):
PATTERN |
2 |
ENVELOPE |
2 |
RATE |
6 |
MIX |
10 |
BANK A/B |
A |
Filter Sliders 1-8 |
All the |
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way up. |
Figure 2 - Basic Settings
Press the stomp switch. The BYPASS light will now turn green. Playing your instrument, set the DRIVE control so that the DRIVE indicator lights up yellow most of the time. You will also hear the filtered signal. Adjust the OUTPUT control so the MuRF’s effected signal is about the same loudness as the bypassed signal.
7) Continue to play your instrument, playing sustained sounds like ringing chords. Your instrument’s signal is going through the MuRF’s filters. Listen to how it affects the quality of your
instrument’s tone. You will hear the level of each of the 8 filters being turned up and down automatically in sequence by the Animation at a tempo determined by the RATE control. Note that changing the ENVELOPE control affects the shape that turns the filters up and down. The PATTERN rotary switch selects different patterns that dictate the sequence that turns the Filters up and down automatically. The MIX control is used to blend the direct sound of your instrument with the effected sound.
8. In the next sections we’ll explain exactly how the MuRF’s Filters work and what the Animation does. For now, get a feel for the controls by experimenting with different settings.
FREQUENCIES and FILTERS
Let’s start with some definitions. Please read this section carefully, as it will help you to understand the basic ideas behind the MF-105 MuRF’s filters.
Sound is a vibration of the air. The speed of vibration is called the frequency. It is measured in Hertz (Hz). One Hz is one vibration per second. We hear vibrations from 20 Hz to 20,000 Hz.
Musical sounds generally have many frequency components. They’re called harmonics, or overtones, or partials. They are
what give a sound its characteristic tone color, or timbre. A graph |
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showing the strength of each of a sound’s harmonics is called |
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a spectrum. A typical spectrum of a musical sound is shown in |
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Figure 3. |
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A filter is a signal- |
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modifying device that colors |
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a sound by emphasizing |
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some parts of the audio |
Figure 3 - Typical spectrum of a musical sound. |
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spectrum and attenuating |
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(cutting down) other parts. In general, a filter has a ‘quality’of |
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its own which is superimposed on the tone color of the original |
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sound. Some types of filters (like the bass and treble controls on your sound system) have subtle, gentle effects on a sound’s timbre. Other types of filters have stronger and more dramatic effects, and are frequently used as vital elements in the music-making process. Strong filters include phasers, flangers, and wah-type resonant filters.
A graph showing what a filter does is called the filter’s frequency response. The horizontal axis is frequency. The vertical axis is the filter’s gain. A gain of “1” (unity) means that, at that frequency, the output of the filter is just as strong as the input. A gain of less than unity means that the filter’s output is attenuated at that frequency, while a gain of greater than unity means that the output is actually greater than the input.
Figure 4 - Frequency responses of typical filters.
Figure 4 shows examples of the frequency response characteristics of two common types of filters: (a) a lowpass filter, which passes frequencies without attenuation up to a so-called ‘cutoff frequency’, and attenuates the frequencies above cutoff; (b) a resonant filter, which emphasizes frequencies around the filter’s ‘center frequency’.
Both of these filter types are widely used in contemporary music performance. Each of them has its own distinct sound, a large part of which is directly related to the shape of its frequency response graph. The first type is embodied in the moogerfooger MF-101 lowpass filter, and the second type is embodied in the MuRF.. There are eight separate resonant filters in your MF-105.
The MuRF’s FILTERS
The MuRF’s eight resonant filters have a fixed center frequency, shown on the legend underneath the filters’sliders. Their frequencies are: 200 Hz, 300 Hz, 450 Hz, 675 Hz, 1 KHz, 1.5 KHz, 2.2 KHz, and 3.4 KHz.
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 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. A graphic equalizer will theoretically not color the signal at all when all the sliders are set to the same level. The MuRF’s resonant filters on the other hand color the signal a great deal, adding warm analog resonances at pleasing intervals through out the frequency spectrum. We’ll now show how the MuRF’s filters affect your MF-105 frequency response. We will always start with this ‘basic’panel setup, which is:
1) Set each of the filters’ 
sliders to all the way up.
2) Switch the PATTERN to Bank A, Pattern 1. Pattern 1 turns off the Animation so you can hear the effect of just the filters.
3) Make sure the effect is on, and MIX is at 10.
Figure 5 - Basic Settings for checking out the filters.
4) Connect just the “left/mono” output to your amplification.
You may want to experiment with the panel controls and switches as we discuss each of the parameters.
5) Now, play a bright, sustained sound, preferably of low pitch into the MuRF - keep in mind that filter effects work by removing frequencies, so you must have a bright sound to hear the effect! Figure 6 shows the MF-105’s basic frequency response, the response that you hear when the panel controls are set up as in the basic setup. Note that there are 8 resonances – they impart warmth and color to the sound. For a moment press the bypass switch and turn the effect off. Note the change in character of the sound. Now switch the effect back on.
Figure 6 – Frequency Response of MuRF in Basic Setup
6) Now turn all the sliders down except the lowest one. Figure 7 shows the frequency response of just the lowest filter. Experiment by turning each slider up one at a time, while the rest of the sliders are all the way down. Pay careful attention to the sound of each filter. When you have learned the sound of each individual filter, try various combinations, such as the bottom two and top two. Note that even without 
Animation, the MuRF is a VERY POWERFUL filter bank with many possibilities to sculpt your tone!
Figure 7 – Frequency response of 200 Hz Filter
7) The Filters’resonant frequencies can be shifted up and down by a small amount to create an effect similar to phasing. Figure 8 shows a graph that portrays the results of shifting a resonant filter’s center frequency. In the MuRF this can be done two ways, depending on the position of the BANK slider switch. The switch, located below the PATTERN selector switch is labeled BANK A
or B/LFO. When the slider is in the “A” position, the filters’center frequencies can be shifted by an expression pedal (such as the Moog EP-1) or CV plugged into the LFO/SWEEP Jack.
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To hear how |
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this works, return |
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to the basic setup |
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described in Figure |
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5. Plug a Moog |
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Figure 8 - Resonant Frequency shift |
EP-1 into the LFO/ |
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SWEEP control |
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input. Then, as you play into the MuRF, rock the EP-1 back and forth. You will hear the filters’frequencies shift with the motion of the pedal.
When the BANK slide switch is in the B/LFO position, an LFO (Low Frequency Oscillator) shifts the frequencies of the filters as a group up and down automatically. The LFO is a sine wave. The rate is determined by the pattern, or an expression pedal (EP-1 or equivalent) or CV connected to the LFO/SWEEP jack.
To hear the effect of the LFO on the MuRF’s filters, return to the basic setup outlined in figure 5, then move the BANK slider switch to “B/LFO”. Now as you play through the MuRF, you’ll hear the filters swept up and down automatically. To change the speed of the LFO, plug a Moog EP-1 expression pedal into the LFO/SWEEP Control Input. The EP-1 can now slow down or speed up the LFO.
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