INTRODUCTION TO SYNTHESIZERS - hol.gr

assign it to the new note. One sounding note will simply disappear - usually the first note that you have
triggered. This side-effect is called "note stealing" and can be quite disturbing when playing large chords with
long sustaining sounds on a four- or eight-voice synthesizer.
Other methods
The synthesis method we looked at in the previous chapters is usually called subtractive synthesis. This means
that the synthesizer starts with a basic waveform (such as a sawtooth-wave) and filters this into a multitude of
variations.
Of course this is not the only way to create sounds. Some synthesizers (like the simplest synthesizer circuits on
many computer soundcards) use a method called frequency modulation or FM for short. This technique is based
on sine waves "modulating" each other. I will not describe this method any further here, but if you would like to
read more about FM-synthesis, please read my page about the Yamaha DX7 synthesizer.
A third synthesis method is called harmonic synthesis. This method uses a large number of sine waves with
different pitches and volumes, which when combined create a complex sound. This method is rather complicated
since it is almost impossible to imagine what the final waveform will sound like before all the parts are combined
together. That's why harmonic synthesis is mainly used together with computers.
One very recent method is software synthesis. A computer software is used to emulate a synthesizer and the
sound chip of the computer is used to create the sounds. The user communicates with the program by using a
set of simulated synthesizer controls on the screen, like pushbuttons, knobs and sliders.
Subtractor Polyphonic Synthesizer (Reason module)
Even it may seem strange first, these software synthesizers are just as useful as any hardware-based
synthesizer, and their capacity is often quite impressing.
There is really no way of telling if a synthesizer heard on a recording is a hardware-based synthesizer or a
software-based one such as ReBirth or VAZ Modular.
Sampling
A sampling synthesizer (or "sampler") has no internally generated sounds at all. Instead it uses external sound
sources - like acoustic instruments, the sounds of nature or the human voice.
Sampling is a digital technology - there are no tapes or other conventional recording devices involved. Instead
the external sound is analyzed by a microprocessor, chopped up into tiny pieces and stored in the sampler's
memory as a huge array of numbers. Once the sound has been recorded or "sampled", it can be mapped over
the keyboard and used exactly as the internal waveforms of the traditional synthesizers.
As recently as fifteen years ago, sampling required
extremely advanced technology, and the few sampling
musical instruments available (like the famous Fairlight
CMI) had price tags like Ferrari sports cars. Operating
these awesome workstations also required a substantial
amount of training.
Fairlight CMI III
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