Natural M2 VOC


Marc Marc (C)2002 

This manual is continuously updating


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All pages & contents: Copyright (C)2002
by Marc Marc Amsterdam


To this manual

This manual will explain all about the Natural M2 VOC musical device - designed in 2002. It is an enhanced design based on elementary research in the field of Vocoder effects.

Not only the technical features and possibilities will be treated but also the musical, spiritual and creative impact will come to an insight on a abstract level. With abstract level is meant that the style of the music one may prefer is of no concern for the abstracts, since this can be seen as a practical matter 'only'.

  • Author of this manual: Marc Marc - Multi Disciplinary Artist / Designer of electronics. EST 1977
  • Date: November 2002
  • Origin: elementary research done from the early eighties until now.

Table of content

To this manual
-- Pandora's Box
-- Specialty
-- Creativity
-- On the fly
-- Open device
-- Alchemy

-- Introduction
-- Abstraction
-- Spectrum
-- Control voltages
-- Transformation
-- Natural
-- Specialty
-- Touch

Optional features
Base version
Optional features
-- More bands
-- Pre-Amp
-- Mixed Output
-- Compander
-- Accent
-- Patch Card
-- Multiple I/O
-- Depth Control
-- Preset Bank
-- Speed Control
-- Additional




Natural M2 VOC


Above: The most extended model at this moment. View all models



The Natural M2 VOC (called "M2VOC" from now on) is a modular analog device based on highly improved classical design techniques and new findings based on extensive research and analysis. With the design of the M2VOC some main classical Vocoder problems are solved. This had lead to a Vocoder with a more natural and musically oriented sound. The M2VOC also features 'rare' options which intend to stimulate the joy for exploring experimental concepts in electronically generated music.


Pandora's box

The design of the M2VOC is a result of years of experience in experimental procedures (patches) with both traditional synthesizer based music and creative research on special procedures - only to be achieved by having the modular features as designed for the M2VOC. The M2VOC can be called a Pandora's box (in a positive way) as most of my musical instrumental design. It offers so many possible patches that it becomes, besides the standards patches, a device full with surprises.



The M2VOC covers many possibilities to generate both classical Vocoder sounds and new to explore experimental sounds. The features of the M2VOC can be split up in three areas. 1) the modular setup which able you to create patches - also with external devices or extra on board inclusions of modules specifically designed for your application. 2) A different approach in the philosophy of achieving the transfer from VOICE to CARRIER signal (resulting in a more musical oriented effect rather than based on speech). 3) An electronic invention which solves a major problem in the all over frequency response of the Vocoder effect (natural vs. robot-like). Both point 2) and 3) are at this moment into a procedure to get a patent.
In the early eighties I worked a lot with a 10 channel only Vocoder in combination with modular synthesizers. I patched up the modular Vocoder together with modular synths in a very alternative way. The M2VOC project not only is to deliver a 24 channel high quality Vocoder as being hardware which has the features to retrieve these original concepts and put them into a practical concept (a sound effect or way of creating sounds) but, also to deliver concepts on a more conceptual level when it comes to using the heritage of analog modular synthesizer technology - no matter the fact that much of this is digitized nowadays. It all goes about a deeper understanding of the electronics (the steps which need to be taken) in relation to a musical fantasy, the lust to create a personalized sound, the passion to achieve something new and of course to have the tools for this all.
The M2VOC is not just another Vocoder concept. Besides the inventions which were made to solve some major problems in both analog AND digital/software Vocoders, it intends to provide you knowledge. To inspire to explore certain possibilities of Vocoder based effects and how they can result into a sound to give a soul to your music production.


Explore your creativity

The M2VOC offers for each musician a range of possibilities to express and explore the desire of creating one's own territory of sounds in a very creative and original way.

Suggestions in this manual will be given in how to start to explore the M2VOC - no matter what musical style you are aiming at. As a musician you have to experiment with these suggestions to find your way among all the features which the M2VOC offers you and how to start thinking creatively with using the M2VOC as part of a total setup with other musical devices, effects - both analog or digital - MIDI based devices with MIDI/CV capabilities and analog synthesizers.


On the fly

While writing this manual I keep in mind that you might not know certain ins en outs which are a need to understand the concept in its full extend but, at the same time it is hard to keep track on this consistently over the entire manual because it is partly written on the fly and never finished. There is no doubt that I will forget to mention about certain experimental possibilities. This, you should consider an advantage rather than a disadvantage because it gives you the necessary space to fill in yourself. There are many issues in this manual which I describe as being standard for my way of working with a modular application such as the M2VOC and are partly based on general standards - those which you should be aware off or learn about. At the same time there is plenty of space given to you by my suggestions to allow your own adoption of this knowledge and find out your very own way of dealing with an application such as the M2VOC. I want you to have fun with it without being a copyist and therefore you will find this manual on your path not as being standard.


Open Device

Another reason that this manual impossibly can cover all the possibilities of the M2VOC is that the character of the M2VOC acts like a "box of Pandora". Besides the more or less standard features and possibilities, it also offers you to explore new ideas, you never came up with before - even when you operate with it already for many years. The M2VOC is an 'open device' - always can be extended with new to add electronics/features or interfacing and most of all: new thoughts to explore.


Alchemy of the heart

Each feature which the M2VOC counts is an abstraction of treating and/or generating so called Voltages and signal paths. These abstracts are the tools to create music - to turn the abstraction into something real which we know as being music in its most widest sense - to turn the abstract thought (or call it a feeling,- an intuition) into an output with the potential to touch ones feelings in a way that is typical for our time - a time wherein technology not yet did found its place. Turn anything into gold - the alchemy of the heart is the beat which dominates the development of technology. Musicians are the ones at focus to give shape to the unknown of the future and at the same time establish the past.




Natural M2 VOC


Let's draw back to the concept of Vocoding a sound in its essence. What exactely does a Vocoder do? To understand how the Vocoder effect is achieved, I will try to guide you trough some basics.



First an abstract description: A Vocoder transfers the dynamics of a VOICE signal - split up in a certain amount of frequency bands - to the CARRIER signal frequency spectrum. As a result (more or less) you can let an instrument 'talk' with your voice. The all over timbre of the instrument remains but appears with the dynamics of both timbre and envelope transformation extracted from the Voice.


Split up the spectrum

A Vocoder has a so called VOICE and CARRIER input. Both Voice and Carrier are split up into a range of frequency band sections - covering together the whole audio frequency band (spectrum). Simple Vocoders count a 10 bands split up. More sophisticated Vocoders, such as the M2VOC split up into 24 bands. This is done with so called BANDPASS filters. Each filter on the VOICE side has its counterpart on the CARRIER side. Thus each filter comes in twins. The more band filters, the better the resolution (the refinement) of the final Vocoder effect but, also the harder to design.


Control voltages

Each output of the Voice filters is followed by a so called Envelope Follower (ENV) to convert the amplitude of the audio band into a Control Voltage. These Control Voltages represent in its dynamic varying the amplitude dynamics of the Voice signal. If you look at the display of a spectrum analyzer (or on a computer view a 'Bars' display when playing a sound with a Media Player), you then will get a clear visual representation on how the levels vary on each frequency band while the music is playing. When the bar goes up, the amplitude of the frequencies within that specific band are high and visa versa. All together the bands represent the ratio of frequency band content within an audio signal.



Each Carrier filter output is followed by a so called VCA (Voltage Controlled Amplifier). These VCA's function as a volume control for each filter to be mixed into the end result. The VCA's are controlled in their amplification by the Control Voltages from the ENV's which do represent the frequency dynamics of the Voice signal. When the Voice signal is silent, no Control Voltages are present and thus all VCA are at zero amplification and thus there is no transformation to the Carrier signal. Nothing can be heard although a Carrier input signal is present. As soon a the Voice is present, each part of the spectrum delivers a Control Voltage according trough the Voice filters and Envelope Followers - representing the Dynamic frequency content of the Voice signal. Then these Voltages control the VCA's in their amplification of each frequency band and thus each frequency band of the Carrier signal is mixed in a creating ratio to recompose the Carrier signal.

The following graphic illustrates this principle in its most primitive way.

At the left side you see a simplified diagram on how a Vocoder is essentially build up from certain standard principles joined together. It does not matter whether this is done with discrete electronics (analog/digital) or by software (digital). "24 X" means that this example handles about a 24 Band (Channel) Vocoder. Thus the diagram is repeated 24 times - each time for a different frequency band. Thus: a 24 Channel Vocoder counts principally 2x24 band filters (24 for the Carrier signal and 24 for the Voice signal), 24 Voltage Controlled Amplifiers (VCA's) and 24 Envelope Followers (ENV's). Of course input and output stages are required but, basically this is the heart of a Vocoder. Everything else which can be add to this concept (and this is a lot) is to serve the user to explore the basic concept of Vocoding and not to forget: to serve a modular setup to explore alternating concepts which are related to the electronics involved but not necessarily intend to be Vocoder related effects (read this statement 3 times before you continue).

At the right hand of the graphic you can see an example of transformation. It shows you the Vocoding of Noise - to give a voice to noise, to let Noise speak (sing or transform any music --> Noisyfie). You can see that the Noise spectrum curve is flat (red line/text). This means that the Noise signal which serves as a Carrier signal contains all frequencies of the audio spectrum (White Noise). The M2VOC includes such a high quality analog Noise Module.
The Voice input diagram (blue) represent a momentary capture of the amplitude dynamics - split up into 24 spectral bands. As you understand, these dynamics continuously change when you speak (or as the singing/music goes). The captured (an arbitrary moment) picture is transformed to the Carrier signal. An thus the flat Noise Carrier input is - after first split up into frequency bands - recomposed to a total noise signal which now has the dynamic frequency band characteristics of the Voice signal. The Noise gets a human soul - becomes alive.
This 'trick' can be done with any input signal. The VOICE and CARRIER labels are only arbitrary for the sake of understanding and to honor the classical Vocoder effect concept. You are free to alternate with this concept (you do not need to involve any voice).



As easy it may seem to design a Vocoder, it turns out to be quite complicated to design it in such a way that the resulting Vocoding effect is more than acceptable. Many manufacturers designed a Vocoder based on the principle which I just described. At first with analog technology which, in commercial releases, was very handicapped. In laboratory and studio versions of these designs the improvements were not leading to a real improvement of the Vocoding effect. This was not only due to the specifications of electronic circuits only. Also the conceptual grounds were weak or simply not adequate. Even today with the software Vocoders - based on very fast computers - still it does not sound right because it lacks the correct philosophy. And if you have a so called fast computer (commercial!) then it still is not fast enough to do the immense calculations needed to achieve an acceptable result.

The conclusion is that: 1) when some electronic design problems can be solved and 2) The conceptual base is alternated, then an analog Vocoder design - as the M2VOC - is superior.

I can imagine that you like to know all about how these new defined conditions which are worked out in the design of the M2VOC. At this stage it is impossible to explain it because it is in copyright protection procedure but, I can give you at least the abstract on this.

1) A technical (electronic) solution to create a more natural filter response.
2) A conceptual different approach which led to a more musically (harmonious) response and functional features.

Also the choice of components (electrical and control parts) is important. The M2VOC will is build with good quality components (no dime screwing). Most components are within a 1% tolerance range. The filter bank components are selected at 0.25% tolerance and the filters are checked afterwards by a computer frequency analysis setup (and corrected if necessary). The feed trough of control signals is minimized below 60 dB (over 70 dB also possible with extra procedure). The M2VOC is designed to electronically function faultless for a minimum period of 25 years.
If you decide to want certain parts/components (control components in particular) on a higher standard (specific industrial or military), this is all possible to discuss.



The illustration below shows you graphical plots which demonstrate the difference between the 'classical' and M2 method.

The blue marked area shows you a plot of the frequency response of the M2VOC with the M2 alternative method. As you can see the response is almost over the entire frequency range flat within plus/minus 1 dB. The drop off in the lowest area an in the highest area easily can be corrected by increasing the gain for those channels a little. With some extra gain tuning for each channel the flatness of the curve can be even improved more. You might think that it is normal to have a reasonable flat response curve from a Vocoder. Wrong!

The gray marked area shows you the classical method. The plot was made with the first prototype of the M2VOC. With exception of the choice of the filter band center frequencies and the bandwidth of the filters, it was designed according the method which is used with all Vocoder designs. As you can see the frequency respond curve is far away from flat. The result was far away from natural - according the classical method. The only good aspect of the M2VOC response in this early stage of development was its match to a more musical effect instead of a voice like effect.

Making the bandwidth of the filters more wide reduces the peaks and gaps in the frequency response line. This is one of the remedies used in classical Vocoder design. But, the disadvantage is that the differentiation between channels becomes worse and thus the Vocoder effect becomes less natural (frequencies which belong in a specific band feed through in the bands which lay aside that band).

The solution of this filter response problem was solved after many hours of analysis, a dramatic moment of feeling to have lost the war and then in a flash a moment of extreme brightness (a moment of true eureka).



The specialty of the M2VOC not only lays in its alternative way of dealing with the band filters to create a natural Vocoder effect response. Nor in the fact of choosing for a more musical approach of filter frequencies. An important specialty of the M2VOC is the possibility to add optional features to have the Vocoder design which fit to your desires and aspirations. All kind of features that are possibly to add (options) will be described in the next chapter. By communication with the client these optional features get shape in a final modular design.

The advantages of a M2VOC modular design are great. They go further than only changing the order of the channel path ways. The details of these possibilities are discussed which each client individually after they are selected for the first production series.



Within my collection of 80 unique recordings (80x 2x45 minutes tapes) I many times invoked a 10 Channel-(only) Vocoder in patches with my modular analog synthesizer to achieve effects based on modular patches (inventions). In particular within the so called 'electronic cover' concept the Vocoder setup involved patches which were extremely interesting to convert certain instrumental aspects of the original music into a completely new associations with my sound or served as a kind of base for a new piece. Often it was not easy to get along with these complexes of transformations but the result was exciting in all means. With certain music it was possible to convert it - with a specific patch - to be transferred into something completely different and very acceptable to serve my musical ideas.
Why putting so much energy in learning to play all these instruments to get to the point of being able to compose and play to achieve a particular musical idea? if it is possible to converts existing music by manipulating it towards ones own idea! Nowadays many musicians use modified sample compositions to do actually the same. A modular Vocoder and understanding of analog synthesizer technologies will bring you an extra opportunity to explore your very own horizon in achieving your own sound an come up with original realizations of these musical feelings.
Of course this was only one possibility to approach a modular Vocoder. The M2VOC also offers you to generate classical Vocoder effects without the complications of making patches.


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