Vector synthesis
Encyclopedia
Vector Synthesis is a type of audio synthesis
introduced by Sequential Circuits
in the Prophet VS synthesizer during 1986. The concept was subsequently used by Yamaha
in the SY22/TG33 and similar instruments and by Korg
in the Wavestation
.
Vector synthesis provides movement in a sound by providing dynamic cross-fading between (usually) four sound sources. The four sound sources are conceptually arranged as the extreme points of X and Y axes, and typically labelled A, B, C and D. A given mix of the four sound sources can be represented by a single point in this 'vector plane'. Movement of the point provides sonic interest and is the power of this technique. Mixing is frequently done using a joystick, although the point can be controlled using envelope generators or LFOs
.
based on those in the PPG Wave
as its four sound sources. The limitations, particularly the digital aliasing
, of this design, coupled with its use of Curtis analogue filter ICs to process the mixed sound, gave the Prophet VS its distinctive sound.
added to the Prophet's implementation of vector synthesis by providing two types of sound source. Each axis of the vector had both an FM sound source
and a sample-playback source.
Although it lacked any filtering, it added digital effects for processing the results of the vector synthesis.
went further still, allowing each of the four sound sources to produce not just a static tone, but a complex wave sequence, by playing back or cross-fading one wave after another.
workstation is one of the first synthesizers for over a decade to feature vector synthesis. It also features an updated form of wave sequencing, like the Wavestation. The Korg Kronos
also features this synthesis.
Synthesizer
A synthesizer is an electronic instrument capable of producing sounds by generating electrical signals of different frequencies. These electrical signals are played through a loudspeaker or set of headphones...
introduced by Sequential Circuits
Sequential Circuits
Sequential Circuits Inc. was a California-based synthesizer company that was founded in the early 1970s by Dave Smith and sold to Yamaha Corporation in 1987. The company, throughout its lifespan, pioneered many groundbreaking technologies and design principles that are often taken for granted in...
in the Prophet VS synthesizer during 1986. The concept was subsequently used by Yamaha
Yamaha (manufacturer)
is a multinational corporation and conglomerate based in Japan with a wide range of products and services, predominantly musical instruments, electronics, motorcycles and power sports equipment.-History:...
in the SY22/TG33 and similar instruments and by Korg
Korg
is a Japanese multinational corporation that manufactures electronic musical instruments, audio processors and guitar pedals, recording equipment, and electronic tuners...
in the Wavestation
Korg Wavestation
The Korg Wavestation is a vector synthesis synthesizer first produced in the early 1990s and later re-released as a software synthesizer in 2004. Its primary innovation was Wave Sequencing, a method of multi-timbral sound generation in which different PCM waveform data are played successively,...
.
Low frequency oscillation
Low-frequency oscillation is an electronic signal, which is usually below 20 Hz and creates a rhythmic pulse or sweep. This pulse or sweep is often used to modulate synthesizers, delay lines and other audio equipment in order to create effects used in the production of electronic music. Audio...
.
Vector synthesis implementations
There have been a number of different implementations of vector synthesis. These differ in what they use for the four sound sources, and what processing is done to the sound after the vector synthesis stage. The actual vector synthesis concept is identical.Prophet VS vector synthesis
The Prophet VS used four digital wavetable oscillatorsWavetable synthesis
Wavetable synthesis is used in certain digital music synthesizers to implement a restricted form of real-time additive synthesis. The technique was first developed by Wolfgang Palm of PPG in the late 1970s and published in 1979, and has since been used as the primary synthesis method in...
based on those in the PPG Wave
PPG Wave
The PPG Wave was an analog / digital synthesizer built by the German company Palm Products GmbH. The PPG Wave used digital waveforms and analog filters and VCAs. The Wave was a combination of a synthesizer and a sequencer, with sequencer relatively advanced with the ability to influence real sounds...
as its four sound sources. The limitations, particularly the digital aliasing
Aliasing
In signal processing and related disciplines, aliasing refers to an effect that causes different signals to become indistinguishable when sampled...
, of this design, coupled with its use of Curtis analogue filter ICs to process the mixed sound, gave the Prophet VS its distinctive sound.
Yamaha SY series
The Yamaha SY22Yamaha SY22
The SY22 is a combined FM/sample-based synthesizer introduced by Yamaha in 1990, building on the vector synthesis technology developed by Sequential Circuits prior to their demise and takeover by Yamaha in 1987. A joystick allows the user to 'morph' between four different sound sources; two FM, and...
added to the Prophet's implementation of vector synthesis by providing two types of sound source. Each axis of the vector had both an FM sound source
Frequency modulation synthesis
A 220 Hz carrier tone modulated by a 440 Hz modulating tone with various choices of modulation index, β. The time domain signals are illustrated above, and the corresponding spectra are shown below ....
and a sample-playback source.
Although it lacked any filtering, it added digital effects for processing the results of the vector synthesis.
Korg Wavestation
The Korg WavestationKorg Wavestation
The Korg Wavestation is a vector synthesis synthesizer first produced in the early 1990s and later re-released as a software synthesizer in 2004. Its primary innovation was Wave Sequencing, a method of multi-timbral sound generation in which different PCM waveform data are played successively,...
went further still, allowing each of the four sound sources to produce not just a static tone, but a complex wave sequence, by playing back or cross-fading one wave after another.
Korg OASYS
The Korg OASYSKorg OASYS
The Korg OASYS was a workstation synthesizer released in early 2005, 1 year after the successful Korg Triton Extreme. Unlike the Triton series, the OASYS was implemented on a custom Linux operating system and was designed to be arbitrarily expandable via software updates, with its functionality...
workstation is one of the first synthesizers for over a decade to feature vector synthesis. It also features an updated form of wave sequencing, like the Wavestation. The Korg Kronos
Korg Kronos
The Kronos is a music workstation manufactured by Korg that combines nine different synthesizer sound engines with a sequencer, digital recorder, effects, a color touchscreen display and a keyboard...
also features this synthesis.
