Additive synthesis - THE ESSENTIAL GUIDE TO

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					  make music now Additive synthesis for beginners

                  THE ESSENTIAL GUIDE TO...                                                                                                                   NEXT MONTH

       Additive synthesis
                                                                           It used to have a reputation for being difficult and
                                                                           unwieldy, but additive synthesis has come of age…

       JARGON BUSTER                                    ack in cm90’s Essential Guide,        on a technique which, in many ways, is    additive synthesis can be difficult to
       3 PARTIAL                                        we looked at subtractive              the exact opposite: additive synthesis.   understand. Hopefully, though, we’ll be
       Partials are what define the
       harmonics present in an additive                 synthesis. As its name suggests,         Although additive synths have been     able to give you a good idea of how it
       synth patch                               this technique is based around the           around for a long time, it's the          all works in this tutorial.
                                                 principle of taking a standard waveform      subtractive sort that have been the           Other barriers to the adoption of
       3 ENVELOPE
       Envelopes can be used to change           and removing (or subtracting) harmonics      mainstay of electronic music for the      additive synthesis have traditionally
       partials over time                        using filters. This month we’re focusing     past few decades, mainly because          been tricky user interfaces and the fact
       3 HARMONICS                                                                                                                      that a fair amount of raw number
       The individual frequency components
       that make up a sound                     THERE’S NEVER BEEN A BETTER                                                             crunching is required if you want to edit
                                                                                                                                        a sound on the fly. Today, however,
                                                                                                                                        we're spoilt by extremely powerful
                                                TIME TO FIND OUT WHAT ADDITIVE                                                          computers and soft synths with
                                                                                                                                        fantastic user interfaces, so there’s

                                                SYNTHESIS HAS TO OFFER                                                                  never been a better time to find out
                                                                                                                                        what additive synthesis has to offer. cm

                GENERATOR SELECT
                These buttons (A to D)
                can be used to                                                                                       RESET BUTTON
                individually set up the                                                                              This can be used to quickly
                four additive generators                                                  PATCH SELECTORS            return Cameleon 5000 to
                                                                                          These two drop-down        its clean, default preset
                                                                                          boxes can be used to
                                                                                          select patch banks
                                                                                          and individual presets

                                                              MORPH TIMELINE
             PATCH SELECTION                                  This graph shows how the
             These drop-down menus                            morph path changes over time
             are used to select a
             different patch for each
             corner of the morph path

                                                                                                                                                   RANDOM MORPH
                                                                                                                                                   Click here to set up a
                                                                                                                                                   random morph path in the
                                                               MORPH PATH
                                                                                                                                                   Morph section to the left
                                                               Use this path to control
                                                               how Cameleon 5000
                                                               morphs between
                                                               patches over time


CMU93.t_guide 028                                                                                                                                                          7/10/05 10:49:51 am
                                                                                Additive synthesis for beginners make music now
                                                                                                                      Q&A focus

           WHAT IS IT?                                                       WHAT'S IT USED FOR?                                                HOW DO I USE IT?
           Contrary to subtractive synthesis, additive                       Most synthesis techniques have some kind of                        You can go about creating a new additive patch
           synthesis involves building a sound up by the                     overall sound associated with them, and additive                   in a number of ways. The traditional approach
           introduction (rather than filtering away) of                      is no exception. While FM (which we covered last                   involves defining partials (ie, the relative volumes
           harmonics. While subtractive synthesis is                         month) calls to mind percussive ‘bong’ or ‘twang’                  of all harmonics) and envelopes (how the partials
           sometimes likened to sculpting (chipping away                     type sounds, additive synthesis is often                           change over time). While using this approach
           stone that's not required), parallels can be drawn                associated with rich, edgy metallic sounds or                      gives you the satisfaction of starting from a
           between additive synthesis and painting, where                    transparent, glassy pads. This means that                          blank canvas, it’s very difficult to produce a
           the artist starts with a blank canvas and adds                    additive synths are most suitable for creating                     decent sound this way. If you want to create
           paint to build up a picture. But just as an artist                atmospheric and abstract music.                                    natural, non-metallic sounds, try to keep the
           can be intimidated by a blank canvas, so it can                       With some work, however, additive synthesis                    levels of the upper harmonics much lower than
           be hard to know where to start with an additive                   can be used to produce a much broader range of                     the first few.
           synth. Fortunately, there are a number of easy                    sounds. The secret is knowing how to avoid                              Many contemporary additive synths enable
           ways to get going (See How do I use it?).                         producing yet another additive-sounding texture                    you to create new patches in alternative ways
               A basic additive synthesis building block is                  (see How Do I Use it?).                                            that are much more instantly gratifying. Probably
           called a partial. Partials are often visualised as a                  We’ll be the first to admit that additive                      the most popular technique is called resynthesis:
           series of vertical bars that represent the levels of              synthesis is not the most accessible method of                     typically, the synth will load a normal audio
           subsequent harmonics. While it’s quite possible                   making sounds and textures. However, as                            sample and analyse its harmonic content over
           to create a tone that uses just                                   computers have become more powerful, additive                      time before calculating the partials to create a
           one partial, the result will be                                                       synths have become easier to                   patch that sounds approximately like the original
           monotonous (quite literally) and                                                      use and you can get                            sample. The partials can then be modified to
           static – about as interesting as                                                       immediate feedback on what                    taste afterwards.
           a pure sine wave or sawtooth.                                                           effect the changes you’re                         Certain additive synthesizers offer more
           The secret to synthesizing                                                              making to a patch are having.                advanced features, which open up a whole new
           interesting sounds is change                                                            Previously, sound designers                  range of creative avenues. Camel Audio’s
           and movement.                                                                            had to wait for additive                    Cameleon 5000, for example, can load image
               To add life to an additive                                                           synths to regenerate the                    files and interpret them as additive patches.
           patch, a partial must alter over                                                         sound from scratch before                   Alternatively, an existing patch can be saved as
           time. You can make it change                                                              they got any response.                     an image file, edited in a standard image editing
           using envelopes or by morphing                                                                                                       application and then reloaded. This technique is
           between different partials in                                                            7 The square route: Cube 2 is ideal         demonstrated in the three-step walkthrough at
           quick succession.                                                                        for the additive apprentice                 the bottom of this page.

           FIVE TO TRY...
           VirSyn Cube 2                         Tiny God Heartburn                   Tiny God Meridian                       ConcreteFX Adder                   Progress Audio Soup

         STEP BY STEP Using Cameleon 5000 to turn images into sound

         1                                                                2                                                                3
              Load Cameleon 5000 ( into your                 Play your keyboard; you should hear something that               Switch back to your host application and click on the H
              host application. Start by pressing the Reset button              resembles the sample you just loaded. Press the Export           button in Generator A (to select harmonics) followed by
              (below the preset menu), and then click on the A tab to           button to save the sound as a BMP image file. Load this          the Import button. Now select the modified image file
         access the first generator. Press the Import button and select   into a graphics editor and either blur or sharpen the image      you saved in the previous step and click OK. Play some more
         a sample to load. The audio will be analysed. >>                 before saving it back to disk. >>                                notes on your keyboard to hear the modified sound.

                                                                                                                                                      TUTORIAL WINTER 2005 COMPUTER MUSIC         | 029

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