The Basics Of Analog Synth Programming

1971 Robert (Bob) Moog created the legendary Minimoog that has been a prototype for the most of synthesizers with reference to how they work, also the modern monsters of today

The sound generates from one or more oscillators, get its character (harsh, smooth etc) by filters, amplifies by amplifiers. Filters as well as amplifiers shapes by envelope generators. The sound can also be modulated (vibrato and pulsating effects) thru an extra lore oscillator - LFO

 

1. OSCILLATOR

Electronic genererated sound source

The early synthesizers had entirely analog oscillators:
- VCO, Voltage Controlled Oscillator

Advantage: Living and warm
Disadvantage: Often instable, that gives an instable pitch

Later analog synthesizers had digital controlled oscillators:
- DCO, Digital Controlled Oscillator

Advantage: Stable, that given a stable pitch
Disadvantage: Not as warm as an analog

 

SETTINGS FOR OSCILLATORS

Waveform
An analog synth generally has one, two or three oscillators with different waveforms, for instance saw tooth wave. The difference between the waveforms is the harmonics, that gives the character of the sound.

Some models also has a Noise Generator, that is an oscillator that creates white or pink Noise

On modern synthesizers the oscillator often is a sampled wave (for instance of a guitar or traditional analog synth wave) instead of an electric generated wave as it is on analog synthesizers.

Pitch
The old Pipe organs in churches had a pipes of different sizes, measured in inches (1 inch is about 2 1/2 cm). The larger pipe the lower pitch. The largest pipes was normally 32'. These terms was applied on the electronic organs when the appeared, for instance the Hammond organs, that was created to relate the old mighty Pipe organs. And that became also the case when the synthesizers (because Bob Moog made it in that way when he created the Minimoog). An oscillator often has terms as 32', 16', 8', 4' and so on, that represent different octaves.

Voices
A synthesizer, unlike an organ, can only play a limited number of voices (the number of keys the will be sounding at the same time). For every voice needs a set of oscillators (as well as filters, amplifiers etc).

For instance: The synthesizer Prophet 5 has five voices, with two oscillators per voice. That's ten oscillators (and one additional Low Frequency Oscillator - LFO, more about that below). At the panel you'll find setting for two oscillators, that are in five settings of the hardware inside the synthesizer (as well as all other components for the sound). These can on Prophet 5 be hooked up together for a giant monophonic sound (only the sound of one key can be heard).

Many older analog synthesizers are monophonic (only one set of oscillator, filter etc) and can therefore be played by just one key (the sound from the other keys will be ignored), for instance the Minimoog, that gives the sound a especial character.

Finally, if the synthesizer has more than one oscillator, they can be mixed in a mixer section

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The control panel of a software emulation of Prophet 5 - Arturia Prophet 5

 

 

2. FILTER

Open up or close the oscillator for different amount of harmonics to pass thru, that gives the character of bright or smooth sound.

The main part of the analog synthesizers had analog filters:
- VCF, Voltage Controlled Filter

Many later analog synthesizers had digital controlled filter:
- DCF, Digital Controlled Filter

There are many different types of filter, but most common are:
LPF, Low Pass Filter, cuts the most high frequency harmonics and pass thru the lower. The name of this parameter use to be Cut Off Frequency (that is breakpoint for the filter).

Another controller that use to be found at analog synthesizers is:
Emphasis (emphasis desired frequencies), also called Resonance, and can be described as a "Woink" in the sound. On some analog synthesizers Emphasis can be set to self oscillating for creating some especial sounds. How it behaves is depending of the envelope generator for the filter (more about that below).

There are many different types of filters, such 2-pole (12dB/octave) and 4-pole (24dB/octave). The most common filters at analog synths are 4-pole. A 4-pole filter is fatter than a 2-pole filter. But booth has it's character.

 

3. AMPLIFIER

Amplifies the signal and are used for adjust the signal that is adjusted by the filter.

The early synthesizers had entirely analog amplifiers
- VCA, Voltage Controlled Amplifier

Later analog synthesizers had digital controlled amplifiers:
- DCA, Digital Controlled Amplifier

4. ENVELOPE GENERATORS

An Envelope Generator, shortened as EG, ENV or ADSR direct the signal path for a
- Filter (VCF, DCF) and/or
- Amplifier (VCA, DCA), or
- Oscillator (VCO/DCO)

An Envelope Generator often has these four parameters:

Attack - The beginning of the sound. Fast or slow attack (or something between)
Decay - The time it takes for the sound to fall from attack to sustain
Sustain - The time it takes for the sound to sustain
Decay - The time it takes for the sound to sustain after the key is released

Therefore the name ADSR - Attack, Decay, Release, Release

Some analog synthesizers has a fifth parameter, but not so common: Delay - the time it takes from the key is pressed down until the sound appears (VCA/DCA) or the filter (VCF/DCF) or pitch for the oscillator (VCO/DCO) to start - DADSR.

Most common are:
- One envelope generator. In that case booth VCF/DCF and VCA/DCA use the same envelope generator
- Two envelope generators. In that case VCF/DCF has its own and VCA/DCA has its own envelope generator
- Three envelope generators. Except that VCF/DCF and VCA/DCA has its own envelope generator, the third EG can be used for for instance VCO/DCO (e.g. pitch)

 

The control panel of a software emulation of Minimoog - Arturia Minimoog V

 

5. LFO

For to creating vibrato, tremolo etc there is a special oscillator that works on low frequencies. Therefore the name LFO - Low Frequency Oscillator, that can modulate:
- The oscillator (VCO/DCO), for puls width or vibrato
- The filter (VCF/DCF), for filter sweep, or
- The amplifier (VCA/DCA), for tremolo

 

6. OTHER COMPONENTS

Different synthesizers can have different other components. Some of the most common are:

- Portamento or Glide. The pitch (VCO/DCO) glides between the keys
- Ring Modulator. For to creating bell sounds and metallic sounds with an analog synthesizer

 

7. HOW TO CREATE SOUNDS WITH AN ANALOG SYNTHESIZER

• Start with your choice of one (or more if you have that option) oscillator and set the pitch and waveform
  
• Set the filter, how bright/soft you will have the sound
  
• Set the amplifier, so for instance a filtered sound not disappear in loudness
  
• Set the envelope generators. Here is the main part of the creating of the sound. Notice that the main part of a sound will happen during the 2 first seconds (after that the most sounds are similar).
  
• Set eventually LFO, portamento etc.

 

8. CLASSIC ANALOG SYNTHESIERS

Some classic analog synthesizers are:

MONOFONIC (the sound can be heard from one key):

• Arp - 2600
• Arp - Odyssey
• Moog - Minimoog
• Moog - Prodigy
• Oxford - Oscar
• SCI - Prophet 1
• Yamaha - SY1

POLYFONIC (the sound can be heard from a specific number of keys)

• Moog - Memorymoog
• Oberheim - Matrix 12
• Oberheim - Xpander
• Roland - Juno 60
• Roland - Juno 106
• Roland - Jupiter 8
• SCI - Prophet 5
• Yamaha - CS80

 

8. IF YOU ARE ABOUT TO BUY AN ANALOG SYNTHESIZER, BE AWARE OF:

• Analog synthesizers are very limited compared to new modern synthesizers. At the other hand they are very good at this limited area
  
• The majority of analog synthesizers has no MIDI, because they were made before MIDI came 1982. But some of them has an interface called CV/Gate that is a kind of Pre-Midi. Its possible in many cases to equip them with MIDI (some times to times major costs)
  
• Analog synthesizers are older synthesizers and are many times affected with faults, instable oscillators etc. Check that up before purchase
  
• Older analog synthesizers has no memory storage, and must be reprogrammed for a new sound. Later analog synthesizers sometimes had memory storage for saving sounds in a sound bank
  
• Today there are software emulations of many of the popular classic analog synthesizers
  
  

 

9. SOFTWARE EMULATED ANALOG SYNTHESIZERS

Today there are plenty of software emulated analog synthesizers, with different quality. They are not perfect copies of the originals, but not far from. And they have MIDI, polyphony (many notes can be played at simultaneously) etc. Some of the better are:

• Arturia Minimoog V - Minimoog - the best emulation so far
  
• Arturia CS80V - Yamaha CS80
  
• GMedia ImpOscar - Oscar
  
• GMedia Oddity - Arp Odyssey
  
• Native Instruments Pro53 - Prophet 5