

                Voxx, The 16-Band Vocoder for ATARI Falcon 030
                        (c)1994 Hans Achim Mueller


                Short User's Manual for Demo_Version.
  
                               INDEX
                               -----
                        1.- Introduction
                        2.- Installation & DEMO-Restrictions
                        3.- Description
                        4.- Operation
                        5.- Some Useful Hints
                        6.- Specifications
                        7.- Availability
  
  
  
1.-     Introduction
  
        This is the Demo-Version of a 16-Band Vocoder effect for the ATARI
        Falcon030 computer. This program is Public Domain and free of charges.
        It can be copied and distributed, if it is done entirely, without any
        changes in the code or this text! Any distribution of mutations,
        improvements, cracks etc. of this program without my written permission
        is illegal!
        
        *************************** IMPORTANT *********************************
        I do not assume any responsability, in any form, for direct or indirect
        damages, that may result from the use of this programm!
        ***********************************************************************

		The german version of this text will follow soon (February).

2.-     Installation

        This Demoversion of Voxx should have the following files:

				File Name      Lenght
 
                VOXXDEMO.PRG   46653
                VOXXMENU.RSC    2454
                VOXX_UPR.RSC   52006
                VOXXENV0.RSC   65438
                VOXXENV8.RSC   61982
                VOXX_PAN.RSC   49128
                VOXXMIX0.RSC   65438
                VOXXMIX8.RSC   61982
                VOXX_DOC.TXT   (This text)
              
              
        Be sure these files are the same length (where specified) in other case
        you have a modified and therefore an ILLEGAL copy!
   
        Voxx requires 512 KB of free memory and runs only on ATARI Falcon030 wih
        a RESOLUTION of at least 640 * 480 and at least 16 COLORS! (VGA Monitor
        or similar). If you do not have these requirements please write me a
        postcard telling your configuration in order to check if it will be
        available and when.
    
        IMPORTANT: Before you start the program please read carefully this
        documentation to avoid startup problems (there are some) that I am trying
        to solve now. Furthermore a Vocoder is a complex effect that requires
        some hints and knowledge to satisfy that what is expected from it!


2.1.-   Restrictions in the DEMO-Version:

        The purpose of a Demo-version is to let the user take an idea of what a
        program can be or do. After deep thoughts about what should be in the
        Demo-version of Voxx, I decided to release it at the conclusion of it's
        developement. I could have released a demo much earlier, but it's screen
        would not have been so impressive like it is now!. Actually the
        Beta-version is ready and this demo is a slightly restricted version of
        it. The restrictions are:

        a.- The options marked with *** are disabled and these are: the Load and
            Save File options, Program Store. 
        
        b.- The program changes (cycles) every 30 seconds to the next user
            program. The user programs are uneditable presets (program Store
            disabled) and some  programs are intentionally missadjusted to
            sound not so good. User adjustments on the actual settings are
            possible at any time, but at least in 30 seconds will be overwritten
            by an automatic selected program. If any accesory is selected and
            the 30 seconds count is reached the accesory window will be
            overdrawn by the new adjustements. This is intentionally and
            harmless. Closing the accesory you get a clean Voxx-screen again.

        To run, copy all files to a FOLDER and be sure the PATH is set to the
        application when starting the program.


3.-     Description

        For all those who do not know what is a Vocoder and how it operates, or
        those that not have a lot of experience with them, I will try to explain
        it as simple as I can: Apparently the Vocoder is a Military residual
        product that was developed to encode the speech in a way that it was
        impossible to be understood by other listeners until they also had a
        Vocoder with the same configuration. The function of a Vocoder is to
        split the speech (FORMANT) or any sound into several Frequency-Bands
        (eg. to analyze each band) and apply the amount of signal in each band
        to another sound (CARRIER), that also is splitted in Frecuency-Bands. In
        other words, the spectrum of the speech was used to FORM the sound of
        the CARRIER. The most analog Vocoder is our own Vocal-System that is
        composed of:
        a.-Vocal chords: who produce the voice (Oscillators)
        b.-Mouth: that forms the vocalization (Filtering and Noise)

        The vocal chords produce a sound (voice) that only can vary the pitch
        but not the sound character. The waveform of this sound is nearby a
        Pulse-Wave eg. rich in Harmonics. The sound character is given by our
        mouth formation (Vocalization). The form and volume of our mouth-cavity
        (including tongue position and mouth aperture) produce a resonance
        cavity that acts like a filter on the voice.
        Any variation of our mouth is a variation in the filter parameters, so
        we can say that we have a Time-Variable-Filter of more complex structure
        than known of analog synthesizers. In addition the same airflow that
        excites the vocal chords also can be/is used to create several noises
        ("s", "r", "t", etc) when it passes the throath, tongue and teeths,
        which are added to the voice and also filtered.

        These variations, slower than the voice's pitch, are variations in the
        frequency-spectrum of our voice. If these spectrum-variations are
        extracted and used to parametrize the spectrum of a sound, similar to
        our voice, we get a synthesis of our voice. This synthesis will be as
        good as the spectrum-analisys and reapplication to the sound are.
    
        A well known example (at least for musicians) is the Jew's harp where
        the instrument creates the sound (voice) and the mouth does the
        vocalization.
    
        A Vocoder is composed of following main sections: The analisys section
        (FORMANT) that extracts the spectrum variations of the vocalization
        source (speech, drums, etc), the voice section (CARRIER) where these
        variations are applied to the target sound (strings, pulsewaves, noises
        etc), something to interconnect both sections (routing MATRIX) and other
        sections, for signal conditioning like GAIN, MIX, PAN and VU-Displays
        etc. The names in uppercase are those I used in Voxx.


3.1.-   Formant section:

        The formant section is composed of 16 Band-Pass-Filters (BPF) for
        different frequencys (like an Equalizer) covering the desired frequency
        spectrum and Envelope Generators (EG's). Each BPF lets pass-through the
        part of the input signal's spectrum that lies around the BPF's center-
        frequency (Fc) attenuating the rest of the signal's spectrum
        proportionally to it's "distance" to The BPF's Fc. In other words this
        stage "slices" the Formant signal in frequency bands. The more bands
        (BPF's) a vocoder has the more precise is the spectrum characteristic it
        can analyze. Each band output ("slice") passes in the next stage to an
        envelope generator to form a envelope for each band, proportional to the
        formant signal's spectrum. As mentioned before, the vocalization is slow
        in relation to the sound, threfore envelopes are used instead of the
        direct BPF's output. The Attack/Decay time of The EG's is adjustable via
        the ENV-Faders to create different effects of vocalization.


3.2.-   Carrier section:

        This section also has 16 BPF with the same Fc's as the formant section
        and again here the the carrier signal is filtered and "sliced" into
        spectrum components but this time the BPF's outputs go to
        Value-Controlled-Amplifiers (identical to synthesizer VCA's but
        controlled by digital Values, not Volts). The control value for these
        amplifiers is supplied by the Formant Envelopes. The result is that each
        Carrier-band output is modulated in amplitude by the amount of signal of
        this band in the Formant signal. If all results are added (MIXed)
        together the result is a "symbiosis" of the "speech" of the formant with
        the "voice" of the carrier.
        This is the principle that makes Talking Instruments talk! (or sing?)


3.3.-   MATRIX:

        In the beginning I mentioned the military purpose of a Vocoder to code
        spoken messages and it was based on arrange the routing (Patching) of
        formant envelopes to the carrier in an unnatural order to make the
        speech/voice not understandable. Only with the reverse routing it would
        be possible to reconstruct partially the original speech. I do not know
        if this was usefull anytime for these purpose, but for musicians and the
        movie-FX-sections (Greetings from Robot-Worlds) I am sure it is . This
        routing is done in Voxx via the MATRIX an it is intended to route the
        formant envelopes to the carrier amplifiers.


3.4.-     Additional sections (at least for Voxx):
    
        I/O-Section:
        This section is for input and output signal gain adjust and level
        display.
    
        SPECTRUM & settings section:
        This section displays the formant spectrum envelopes and allows some
        global settings for envelope modes.

        MIX/PAN section:
        The resulting signal is adjustable in this section via the MIX faders
        and the PAN knobs for each band similar to an equalizer.



4.-     OPERATION:

        This long description (I hope, I have reached something more than
        confuse you) is followed now by the operation of Voxx.


4.1.-   Connecting the Falcon030 :

        IMPORTANT!
        The Falcon030 audio inputs are designed for microphone signals and very
        sensitive. If you connect them with a LINE-Output of instruments,
        CD-players or other audio devices be carefull with the levels. In this
        case the better way is to insert 200K Resistors in series with the
        audio-source and the Falcon030 Inputs as in Fig. 1 to reduce Noise and
        Humm. For more information about this, contact ATARI Corp. or your local
        dealer.

                                      Fig. 1
        .......................................................................
        :                                                                     :
        : Instrument                         Resistor       Falcon030 Inputs  :
        :                                                                     :
        :                  Shielded Cable   +------+                          :
        :  Line-Out-Left  ==================| 200K |=============-  Left      :
        :                                   +------+                          :
        :                                                                     :
        :                  Shielded Cable   +------+                          :
        :  Line-Out-Right ==================| 200K |=============-  Right     :
        :                                   +------+                          :
        :                                                                     :
        :                                                                     :
        :.....................................................................:

      
        To connect the Falcon030 for use as Vocoder effect you need:
    
        FORMANT sound source like a MICROPHONE, Tape deck, musical instrument,
        etc, connected to the Left-Input of the Falcon030.

        CARRIER sound source  like SYNTHESIZER, elctric guitar, etc connected to
        the Right-Input of the Falcon030.
    
        A headphone, amplifier etc, connected to the Falcon030 stereo output.

        NOTE: Uppercase devices are the most used in a Vocoder effect (see
        chapter 5.)


4.2.-   Voxx-Screen:

        The following is a blockdiagramm of the Voxx Vocoder as it is arranged
        in the screen:

        ------------------------------------------------------------------------
         "Desk"  "File"                   Menu Bar
        ------------------------------------------------------------------------
         I/O Section          Spectrum & settings                 Matrix
        +------------+  +----------------------------+  +----------------------+
        | ####  #### |  | ########################## |  |  F                   |
        | ####  #### |  | ########################## |  |  E                   |
        | ####  #### |  | ########################## |  |  D                   |
        | ####  #### |  | ########################## |  |  :                   |
        | ####  #### |  | ########################## |  |  :                   |
        | F  C  L  R |  |                            |  |  2                   |
        | O  A  O  O |  |  P1 P2 P3 P4 P5 P6 P7 P8   |  |  1                   |
        | R  R  U  U |  |                            |  |  0                   |
        | M  R  T  T |  | FREEZE SLOW FAST STORE_PRG |  | RST 0 1 2 .... D E F |
        +------------+  +----------------------------+  +----------------------+
        +-------------------------------------------------------------+ +------+
        |  E                                                          | | Voxx |
        |  N                     16 ENV-Faders                        | |  F   |
        |  V                                                          | |  U   |
        +-------------------------------------------------------------+ |  T   |
        +-------------------------------------------------------------+ |  U   |
        |  PAN                   16 PAN-Knobs                         | |  R   |
        +-------------------------------------------------------------+ |  E   |
        +-------------------------------------------------------------+ |      |
        |  M                                                          | |  U   |
        |  I                     16 MIX-Faders                        | |  S   |
        |  X                                                          | |  E   |
        +-------------------------------------------------------------+ +------+
        "#" = Displays


4.3.-   Menu bar

        The menu bar is composed of the titles "Desk" and "File"
    

4.3.1.- "Desk" is the menu for the options:

        -  About Voxx..: which shows the program's version and Users
           Registration.
       
        -  The other options are the accesories your system has installed.


4.3.2.- "File" is the menu for Loading, Saving a file and Quit the program.

***     -  Load File: Loads a file with the settings for 8 user programs
           and the previous saved memory settings.

***     -  Save File: Saves a user file with the 8 user programs as well
           as the actual memory settings.
    
        NOTE: The file extensions are predefined as "VXD" (VoxX Data)
    
        -  Quit: Exits the program.


4.4.-   I/O Section

        The I/O section is  composed of 2 VU-Displays for Input and Output
        levels, Left and Right each. The left input of the ATARI Falcon030 is
        for the FORMANT (speech) and the right input for the CARRIER (voice
        instrument). The output is the stereo effect (Left and Right). The 4
        faders below are for adjustment of the input and output levels. To move
        a fader, point it with the mouse and press the left button, holding it
        (the arrow will change to a hand), now you can move the mouse up and
        down to adjust the selected level. The slider will follow within his
        limits while the left mouse button is pressed.


4.5.-   Spectrum and settings section

        The large display, shows the actual envelope value for each CARRIER-band
        that is extracted from the Formant source, like a spectrum analyzer. The
        frequncy for each band is displayed below. The program buttons allow the
        selection of 8 user setting programs that are loaded at the start of the
        program or via the "Load File" option in the Menu title "File". These
        are user programs. Each of these programs holds the settings for all
        adjustable parameters. Pressing a program button, the selected program
        is copied to the edit memory . Each change in the adjustements is done
        in the edit memory (those that are active). If you want to store these
        settings for future use you must write them to one of the 8 user
        programs (see STORE PRG) and then save them with he option "Save File"
        in the menu title "File".
        Of the 4 buttons at the bottom the 3 named FREEZE, ENV SLOW and ENV FAST
        are for a global range setting of the formant envelope attack/deacy
        velocity.

        FREEZE sets all attack/decay velocities to zero regardless of the ENV
        fader settings, freezing all actual envelope values until another
        button, SLOW or FAST is pressed. This function is usefull to equalize
        the CARRIER with a FORMANT's spectrum characteristic.

        SLOW and FAST set two different envelope velocity ranges with a relation
        1 to 10.
             
***     The STORE PRG button is to store the actual settings (in memory) in one
        of the 8 available programs. To store a program press STORE PRG, all
        the program buttons will then show pressed and then press the program
        button where you wish to save the settings. The settings will be
        recalled each time you press the selected program button.
             

4.6.-   The MATRIX

        The matrix is used to connect the FORMANT Envelopes to the CARRIER
        amplifiers. For each band there is a FORMANT(source) button(green) and a
        CARRIER(target) button (yellow) labeled from 0 to F, where the 0 stands
        for the lowest frequency band and F for the highest. With this matrix it
        is possible to assign or route the envelope of one determinated
        frequency band to any of the CARRIER-band-amplifier. So you can assign a
        low frequency amount in the FORMANT to modulate a high frequency band of
        the  CARRIER and vice versa. In a 1 to 1 routing the effect of a talking
        instrument is the most notable while the shifting of the bands in both
        directions by one or two (0 with 1, 1 with 2, ... E with F  or
        vice versa) adds the effect of pitch shifting (which is the logical
        consequence of shifting the bands). Very scarammbled routings may result
        in interesant and unespected effects of vocalization that surely will
        not be understood as human speech, regardless of what source for the
        FORMANT is used.
             
        The RST button ReSTores the 1 to 1 routing of the MATRIX for comfort.
             
        To operate in the matrix is very simple, then once the mouse enters the
        routing field, it's pointer transforms in a cross that intersects with
        both the FORMANT and CARRIER band buttons. If you want to connect
        FORMANT band 5 to CARRIER band E place the cross in the position where
        the green button "5" and the yellow button "E" are pointed by the
        horizontal and the vertical lines respectively, then press the left
        mouse button and the routing will be done. You can do this routing as
        you like. A FORMANT source can be routed to one or more CARRIER targets
        but a CARRIER target can only recive one source. This means that if a
        source is routed to more than one target there will be one or more
        sources without a respective target.  Leaving the routing field returns
        the mouse pointer to the usual arrow.


4.7.-   ENV section

        This section consists of 16 faders each one assigned to a frequency
        band. According to the range selected with the ENV SLOW/FAST buttons it
        is possible to adjust the attack/decay for each FORMANT envelope. The
        lowest slider position is for slowest and the highest for fastest
        attack/decay times. These sliders are moved by pressing the left mouse
        button while it is positioned in one of the faders and keeping the
        button pressed moving the mouse up and down (pointer is now a hand).
      
        A speciality for this section as well as for the MIX section is that if
        you move the mouse pointer over another fader of this section while the
        button is pressed, then the new pointed fader becomes active leaving the
        one before in the last position. With this method it is possible to
        "draw" the slider positions with the mouse, moving it over the entire
        fader section. In this way it is possible to slide all faders down or up
        by entering in one fader, pressing the left mouse button and holding it,
        to travel the mouse pointer accross the entire screen. While the mouse
        button is pressed the only affected faders will be those of the section
        where the mouse pointer was in the moment the left button was pressed.


4.8.-   PAN section

        Since the FORMANT (left input) and the CARRIER (right input) are used
        both to form one signal, this section is for adjusting the stereo
        panorama position for each modulated CARRIER band (result output), to
        create a stereo effect.
        It is provided with 16 knobs (potentiometer simulations), one for each
        band. To move one of these knobs move the mouse pointer to it and press
        the left mouse button and while holding it, move the pointer around the
        knob. While the left button is pressed the knob mark will point in the
        direction of the mouse pionter over the entire screen.
             
             
4.9.-   MIX section

        The result of each coded band now is ready and with this section it is
        possible to adjust the gain for each band (equalize) to fit the desired
        tone characteristic. The MIX faders are adjusted in the same way as the
        ENV faders.
             
        Additional information: When any adjusting element is being changed
        (faders and knobs), each variation is inmediatly send to the DSP (and
        not when the left mouse button is released). You will hear the changes
        in realtime (as fast as realtime is possible). This has a disadvantage:
        The faders are a little slower than those that are commonly used to set
        parameters (here the information is actualized after the change/movement
        is completed by releasing the mouse button. I think that for a musical
        effect, realtime is a more important factor than fast slider animation.
        Recalling a program also involves sending all parameters to The DSP.


5.-     Some Useful Hints

        Experience has shown that the use of a vocoder could be frustrating for
        some users due to bad understanding of it's operation and what the user
        wants to do with it. My shortest explanation of a vocoder I ever had
        given to those who asked me "what is a vocoder?", was:

               "it is like a good equalizer acting over a sound (CARRIER) whose
                gain controls are fastly moved by a device that extracts the
                movement information from the frequency spectrum of another
                sound or speech (FORMANT)."

        To obtain a good vocoder effect it is important to know what kind of
        effect is expected and what FORMANT and CARRIER sound sources are used.
        The most applications use speech as a source for the FORMANT and
        synthesizer-sounds for the CARRIER.
     
        The FORMANT sources like speech should be clear and cover the most part
        of the spectrum (use the display). A thin voice like through a phone or
        a smooth one (like mine) are very poor in the spectrum's "Skyline". A
        very good speech source is that of the News Speaker in the FM/UKW-Radio
        (They have all the equipment to fill the spectrum with speech). I
        hearthly recommend this test! If using your own voice try not to sing or
        vary the pitch according to the music (else your spectrum moves with or
        against the spectrum of the carrier creating unregular highs and lows in
        level). Remember that the most part of the voice (sound) of the FORMANT
        is discarded, depending on the envelope settings, and only the
        vocalization is extracted. Drums or other percussions are also used as
        formant to create rythmic vocalizations of an instrument. Here the
        limits and settings are unlimited and depend of your imagination.

        CARRIER sources should be rich in harmonics and these are all those
        clear and sharp sounds like Strings, Brass and all those sounds whose
        waveform is based on sawtooth and pulses. Square, triangle and sine
        waveform based sounds (smooth ones) like Flutes, Whistles and some
        organs aren't good ones. Their harmonics are very small in relation
        with the fundamental which will dominate the spectrum (a true sine has
        no harmonics) and the resulting sound will be only in the bands near the
        fundamental's frequency band. The CARRIER's pitch is the pitch for the
        resulting effect, here is where the melody, chords or whatever should be
        played.
     
        I will try to list the effects and the best settings as well as sources
        for each one:

      
        a)  Talking (singing) instruments, Choirs, Backgrounds, Harmonization:
          
            FORMANT : Human Speech
            CARRIER : Strings, Brass, Sawtoths, Pulses playing the melody or
                      accompainement chords.
            Settings: Envelope SLOW
                      ENV Faders: upper positions
                      MATRIX: 1 to 1 or shifted by one or two
                      or
                      Envelope FAST
                      ENV Faders: lowest positions (in upper positions FORMANT's
                                  pitch adds to the result)

      
        b)  Robots:
          
            FORMANT : Human Speech
            CARRIER : Strings, Brass, Pulses, Sawtoths,  with constant pitch
                      (no melody) or steady chords.
            Settings: Like a)
                   
      
        c)  Solist Singer           
          
            FORMANT : Human Speech
            CARRIER : Strings, Brass, Pulses, Sawtoths,  with monophonic
                      (one Finger) melody (synthesizer options like DUAL,
                      UNISON, FAT, PORTAMENTO etc have very good results)
            Settings: Like a)

      
        d)  Rythmic Chords and sounds         
          
            FORMANT : Drums, percussions
            CARRIER : Strings, Brass, Pulses, Sawtoths, etc.
            Settings: All Envelope settings (except FREEZE)


        e)  Warm instrument contouring (variable filtering)

            FORMANT : No limits
            CARRIER : No limits
            Settings: All Envelope settings (except FREEZE)


        e)  Equalizer (fixed filtering):

            FORMANT : Blows in the micrphone Noise or any sound
            CARRIER : No limits
            Settings: First envelope SLOW or FAST.
                      When the spectrum display reaches a desired
                      characteristic press FREEZE
                      or
                      using Noise or blowing the micro and pressing
                      FREEZE when spectrum display is equally leveled.
                      Use the MIX faders to equalize the sound.


6.-     SPECIFICATIONS

        The following are the main Voxx specifications:
              
        Number of Bands   : 16 FORMANT Filters and 16 CARRIER Filters
              
        Filter Types      : Digital-IIR, 4-Pole Band-Pass
              
        Center Frequencys : 125, 160, 210, 275, 360, 460, 600, 780, 1020,
                            1325, 1725, 2250, 2900, 3800, 5000 and 6400 Hz.
              
        Sampling Rate     : 20.77 kHz, 16 Bit Stereo
              
        DSP Usage         : 100%
              
        Dimensions(Pixels): 630 x 460 x 1 Pixels (W x H x D)
              
        Memory Consumption: aprox. 512 kB


7.-     AVAILABILITY of Voxx Version 1.00

        Voxx will be available in it's version 1.00 in March 1994!
              
        Voxx will consist of a Diskette with the program, a	printed
        user's manual similar to this one, in German or English.

        Support and Updating: I will try to support any problems that may appear
        in the use of Voxx only to registered users, and to Update this
        program. The Update prices for registered users will only be those 
        for material + handling.
              
        In the Future: Depending on Voxx's acceptance I am planning to MIDIfy
        Voxx, and for experienced users, add a Filter Editor to change the, BPF
        parameters like Resonance and Center Frequency. Any written sugestions
        are welcome and if possible will be considered!
              
        Coming Next: Pterodaktilus The Synthesizer(s) for Falcon030

        Problems and errors with the Demo-Version:
        As far as I have tested and know, this demo runs without any notable
        error. There may be some problem when starting Voxx: The Spectrum
        Display will overdrive, at the output may be only noise and any attempt
        to reduce the Levels will be without effect. Solution: Start again
        and/or Cold Reset (Set amplifier inputs and volume low!). I am trying to
        solve this problem. If any error or strange effect occur please let me
        know! I will try to fix it. I have programmed and use Voxx myself with
        my Falcon030, as it comes from factory, without changes, additions or
        hardware upgrades with TOS 4.02 and 4.04.
        
        Multitos and Voxx: I recommend to use Voxx in the normal TOS mode
        (Single Task). Due to the intense communication  between Voxx and the
        DSP, I doubt if there is time enough left for "Multitosing".
        
        Prices will be:
        Germany: DM 195,- (+ Porto und Verpackung, z.Zt. nur V-Scheck)  
        Rest of Europe: DM 195,- (+ Postage & Packaging, Eurocheque Only)
              
        Contact to:
                        Hans Achim Mueller
                        Nadlerstr. 6
                        D-69214 Eppelheim
                        GERMANY
                                              
        Distributor inquiries are welcome!                                           

        January, 1994

