Synthesizer

A synthesizer ( [ zʏntəsa ͜ izɐ ]; English pronunciation [ sɪnθəsaɪzɚ ] ) is a musical instrument that produces sound electronically via synthesis sounds. He is one of the central tools in the production of electronic music. We distinguish analog and digital synthesizers. As in many other areas of technology digital devices have analog technology almost completely replaced. Many older analog devices are, however, still used because of their characteristic properties and some have achieved cult status among musicians. The characteristic sound of certain common equipment and the creative use of their own species has often influenced the development of entire genres, such as acid house and techno.

• 4.1 Frequency modulation
• 4.2 Sound Sampling
• 4.3 workstations
• 4.4 Physical modeling synthesizer
• 4.5 Hybrid Synthesizer
• 4.6 software synthesizer
• 4.7 Digital sound production
• 4.8 mobile synthesizer

• 5.1 vocoder
• 5.2 oscillator
• 5.3 MIDI
• 5.4 Sound Module
• 5.5 sequencer

Sound synthesis and effects filters

• Additive Synthesis
• FM synthesis
• Granular synthesis; Graintable synthesis
• LA- Linear Arithmetic synthesis
• Physical Modelling
• Pulse-width modulation
• Sample and Hold
• Sound Sampling
• Subtractive synthesis
• VL Virtual synthesis
• Virtual -to-analog synthesis
• Wavetable-Synthese/auch Phase Distortion synthesis

Electric Phone

Electric organs based on the principle of additive synthesis in which multiple sine sounds mixed together produce a complex sound. In the original Hammond organ from 1935, the sine waves were generated over shaft driven gears which induced vibrations in pickups; for each harmonic were each a wheel Later, the vibrations generated by electronic circuits. The sounds generated by electronic organs were much less modulated than the synthesizer, but had the advantage of being polyphonically.

1950 RCA produced experimental devices for generating speech and music.

In New York Laboratory for Radio Corporation of America, the engineers Harry Olson and Herbert Belar Ferdinand constructed a paper tape controlled device, the RCA synthesizer Mark I. Here were generated tones through tuning fork oscillators; The sinusoidal oscillations were electromagnetically removed and converted into harmonically rich sawtooth waves. Above all, the composer Milton Babbitt dealt with this apparatus and was also a consultant for the successor model Mark II, which was made ​​at the Columbia - Princeton Electronic Music Center.

The Mark II Music Synthesizer (1958 ) could only after complete programming play a piece and had to be reprogrammed for the next. He was controlled via tape. Developed in 1958 Daphne Oram at the BBC Radiophonic Workshop a novel synthesizer, which used the so-called " Oramics " technique. Was controlled synthesizer on 35 mm film. It was used a few years at the BBC.

Hugh Le Caine, John Hanert, Raymond Scott, Percy Grainger ( with Burnett Cross) and other built in the late 1940s and 1950s, various electronic musical instruments. From the 1960s the development of the electronics had progressed so far that sounds and tones could be generated in real time, but these devices were limited to the studio, because of their size. These devices were generally of modular design, and the individual components have been manually wired together. Many of these first devices were experimental and unique pieces. Donald Buchla, Hugh Le Caine, Raymond Scott and Paul Ketoff were the pioneers in the 1960s, with only Buchla offered a commercial device.

Analog synthesizers

Monophonic

The first play and configurable set forth synthesizer Robert Moog and presented it in 1964 to the "Audio Engineering Society convention". Already during the development he could (later Wendy Carlos ) inspire the musician Walter Carlos for the modular synthesizer. The new sound, just like on the " best-selling classical music album " Switched-On Bach by Walter Carlos 1968, was sensational.

In the late 1960s, a variety of shots that used the new Moog synthesizer sound appeared. To the fame piece of popcorn, which became the world's top hit and was created as the first complete with the Moog synthesizer was. The Beatles used on their album Abbey Road discreetly a Moog to miss, for example, the closing refrain of Here Comes the Sun an airy " smart " sound.

Moog sat at the same time the standards that allowed the linking of various synthesizers, such as an interface for external control via a logarithmic 1-Volt/Oktave-Tonhöhensteuerung. The control of the synthesizer usually carried out on a normal keyboard or a sequencer, where you could program pitch sequences in time and which activated the synthesizer via said interface.

Since the Moog Modular system, however, was for the stage and live use too large and cumbersome to use, integrated Moog the most important components of his synthesizer into a compact body, which was given the name Minimoog and 1970, came on the market. The Minimoog was used by several musicians and widely used musical instrument in the following years. During the 1970s, several other companies came with synthesizers on the market, including ARP Instruments ( by Alan Robert Pearlman ), Oberheim (of Tom Oberheim ) and Sequential Circuits. However, all synthesizer had two major drawbacks: Firstly, it was only monophonic play, and on the other they were not permanent program, so you could not save any settings.

Nevertheless, groups and musicians such as Pink Floyd, Human League, Emerson, Lake and Palmer, Kraftwerk, Jean Michel Jarre, Tangerine Dream, Ed Starink, Klaus Schulze or Vangelis on synthesizers specialized. The rock band The Who made ​​use of in their song Will not Get Fooled Again (1971 ) a synthesizer controlled by a sequencer.

Polyphonic

Most of the first synthesizers were monophonic. Only a few were able to produce two sounds at the same time as the Moog Sonic Six, the ARP Odyssey and EML 101 True polyphony was to realize at the time just about the principle of the electric organ ( Oktavteiler principle). The ARP Omni, Moog Opus 3 Polymoog and therefore combined both elements.

Only in 1976 the first true polyphonic synthesizer came on the market: the Yamaha CS- 80 and the Oberheim Four -Voice. These first synthesizers were but complex and expensive. The first affordable polyphonic and also microprocessor controlled and programmable synthesizer so that 1978 was the Prophet -5 from Sequential Circuits. For the first time musicians were able to save your settings and recall them by pressing a button. He was also - compared to modular systems - compact and lightweight.

Analogue sound generation

Analog synthesizers of the 1970s are often constructed as a modular system. The individual components (signal generators, filters, modulators ) are mounted in a rack and interconnected as required by jack cable ( or via a patchbay ).

A tone is usually composed of a root, which determines the pitch and overtones - also known as partials or harmonic tones - that determine the sound color. So Various sounds produced by different types of structure of the overtone series. The individual harmonics differ while in frequency, amplitude and in temporal and dismantling. The sound generation in the analog synthesizer you went based on mechanical instruments first of a few basic waveforms: the wagging ( like strings ), the square wave ( woodwind similar ) and the triangular wave ( flute similar). See: Signal Generator

Voltage Controlled Oscillator (VCO )

The VCO is the most important building block is in analog synthesizers; This is an electronic oscillating circuit, the sound frequency depends on a control voltage. With the simultaneous use of multiple oscillators increases the number of tonal shaping possibilities, the slight detuning of the oscillators against each other is often used ( in unison or beat, similar to a chorus effect ). The Oszillatorenart Digitally Controlled Oscillator is digitally controlled by a microprocessor, although the sound production principle remains analog.

Noise Generator (NG)

In analogy to the spectral energy distribution in white light is called white noise if all audible frequencies occur in a sound mixture in approximately equal proportions. To Colored noise is at a disturbance of these frequency - uniform distribution (if a frequency range is dominant). Some Synthesizers have the ability to produce 1/f-noise, in which prevail low frequencies. In addition to the combination with VCO as a supplier of complex audio signals noise can also be used as a modulation source. In this way, unusual and interesting sounds.

Voltage Controlled Filter (VCF)

The actual sound shaping takes place in the voltage-controlled filter (VCF) - the most commonly used filter is the low-pass filter. The high pass filter works just the opposite. The series connection of low-and high -pass filters results in a band-pass filter; a band-stop filter is created in parallel. Here's a specific frequency band is attenuated, while the remaining frequency components pass through unhindered. In general, you can choose between filtering at 12 dB ( soft) and 24 dB ( hard) slope.

Voltage Controlled Amplifier (VCA )

The voltage controlled amplifier controls the sound parameters by dynamic linear or exponential function of the voltage. As a synthesizer module of the VCA is controlled mainly by the envelope generator. In almost all manufacturers, however, the VCA does not work as a real amplifier, but only as a reducer, and is partly therefore also called Voltage Controlled Attenuator = attenuator. Only with Moog Modular systems can be found both: Amplifier and Attenuator modules.

The envelope

Envelope generators produce programmable voltage processes that are used on the VCA for dynamic control "microscopic " field of a sound, but also the timbre dynamic control of filters ( VCF). Envelope generators are often designed as ADSR generators can then be typically four different parameters programmed: Anschwellzeit ( Attack Time), decay time (decay time), duration level ( the sustain level ) and decay ( release time ). The ADSR generator is started, for example, when key pressed. The name ADSR is formed from the initial letters of the parameter names: Attack, Decay, Sustain, Release.

The modulation

The synthesizer module LFO ( Low Frequency Oscillator) consists of a controllable oscillator with very low frequency. Is modulated, for example, the VCF with the different waveforms of the LFO can be generated in the coupling of two filters to bandpass or inhibit different effect variations such as wah-wah or phaser. When modulating the VCA by sinusoidal or triangular LFO signals, however, produces a tremolo. A square wave LFO then provides a constant repetition of the sound (mandolin effect). Controls the LFO VCO, such as vibrato effects or siren- like sounds can be generated.

Sample -and- Hold

From a noise signal, a sample (English sample) is taken and recorded as a voltage level at regular intervals. When VCO control with such a signal, the pitch changes randomly, whereas the tones at VCF control ( spectral modulation ) randomly lightening and darkening, which can generate a " bubbling " or removed speech-like impression.

Frequency followers

In this module, the pitch of a signal into a corresponding control voltage is converted; so that it works exactly the reverse principle of a VCO. The difficulty is to minimize the time required to detect the pitch. Because multiple wavelengths at a frequency necessary for their identification, results at low frequencies a longer detection time than at higher tones.

Envelope Follower

This module converts the volume gradient or a frequency to a corresponding voltage profile.

Ring Modulator

A ring modulator multiplies two signals together. The resulting signal consists of the sum and difference frequencies of the harmonics of the two input signals. If the frequencies of the two signals form simple ratios obtained usually also harmonic sounds. However one chooses different frequency ratios arise, for example metallic or bell-like sounds that can be used for creating rhythmic or percussive sounds well. The flexibility in immediate electronic conversion of any sound results can has become a preferred method of live electronics ring modulation. In modern synthesizers, perform the ring modulation on a purely mathematical way, you can also adjust the modulation depths of history and therefore change the tone during the Tonverlaufes.

Resonance filter

This module is used for electronic replica of formants. In the filter stage of synthesizers ( the main filter is usually the VCF) is also spoken by resonant filters when the filter ( " ringing" ) parametric resonance can be driven: Exploited states is usually overshoot behavior of filters at or just before the peak frequency.

If this overshoot sufficiently amplified by feedback within the filter stage, the filter can even be placed in self- excitation (without any input signal by the VCO ). The set filter frequency thus also determines the pitch ( "pipes" ) of the self-oscillation. Audible is the resonance ( the self-resonance ), when using the keyboard ADSR envelope opens the VCA. Both without and in combination with the actual tone generation stage (VCO or noise generators ) extended a eigenresonantes filter significantly the scope of the sonic possibilities of a synthesizer.

Analog sequencer

Analog sequencer produce automatic voltage control processes and trigger signals that can be used for the control of all voltage-controlled synthesizer module. Analog synthesizers can also be controlled by digital sequencers. Today digital sequencer in turn are controlled by microprocessors. A distinction is hardware and software sequencer.

Digital Synthesizer

Frequency modulation

A real revolution was the advent of synthesizers with digital sound production, first by FM synthesis. This is possible in principle also to the analog oscillator by an oscillator is modulated by a second oscillator with a frequency in the audible range, but only in the 1970's the digital form was developed which allowed for a very convenient application of the FM synthesis. In short (so-called operators) different sinusoids that modulate each other in response to a selected algorithm, so that complex waveforms can arise in the FM synthesis digital oscillators. A unique feature of FM synthesis, in contrast to the then usual subtractive synthesis was the ability to create very rich in harmonics and percussive sounds.

The patent of FM synthesis was licensed by the Japanese musical instrument manufacturer Yamaha. The first synthesizer, the GS -1 and GS-2, were heavy and expensive equipment and found no widespread. In 1983 appeared with the DX7 synthesizer that would revolutionize the entire market and the ousted analog synthesizer. He had the size and weight of the Prophet-5 and was relatively inexpensive. He was "the " Synthesizer of the 1980s, and there is barely a pop music recording from that time on the no DX7 is heard. After the expiry of patent protection found the FM synthesis widespread, eg in simple 4 operator synths on PC sound cards.

Sound Sampling

A second revolution, which in 1979 announced with the first Fairlight CMI was the sampling. When sampling natural sounds are digitized. These digital waveforms then form the basis of sound production. The sampler was something possible, which only the magnetic tapes with functioning analog Mellotron was previously reserved for the real rate of reproduction of acoustic instruments.

The first systems such as the Fairlight CMI, the emulator I of E -MU or later the Synclavier from New England Digital, were extremely expensive devices that were only the "big " in the industry reserved. In addition, the technical possibilities of reproduction were initially limited because of the low resolution and storage capacity. Peter Gabriel and Kate Bush, published 1982, the first shots in which " sampled " sound can be heard. In 1985, with the Mirage Ensoniq the first affordable for the masses sampler on the market. Sampling coined soon the sound of pop music of the 1980s. Today can be loaded and used for computer-based musical arrangements with a computer and sound card sampling extensive libraries.

Workstations

In 1987, with the Roland D-50 synthesizer on the market, which became very popular because of its sound production ( reproduction of acoustic instrument sounds using a combination of attack samples and basic waveforms, with integrated effects unit ). In 1988, Korg M1 with the integration continues. The M1 represented a new type of synthesizer, which " workstation ". Here for the first time synthesizers, effects, drum machines and sequencers were integrated into one device. This allowed the creation of complete musical sequences in a single device without external hardware. The Korg M1 is so far the best-selling synthesizer according to the Yamaha DX7.

Synthesizer workstations, there are now available as a software (eg Synthesizer Workstation Pro), which do not require any hardware (except the PC) more. They are played via arpeggiator or a MIDI file. Optionally, a keyboard can be connected.

Physical modeling synthesizer

In the early 1990s the first synthesizer came up with a novel synthesis method, the physical modeling on the market. In the PM- synthesis is an attempt to simulate digitally using mathematical descriptions a "natural" physical sound production, that is, one calculates how about air vibrations behave in a saxophone or swinging a string of a guitar.

The have long known principle could be put into practice only with the development of the Karplus-Strong algorithm and its refinement as well as the generalization of the algorithm in a digital waveguide synthesis by Julius O. Smith III et al. For real-time calculation performance digital signal processors ( DSP: Digital Signal Processor) was necessary as they were available only in the late 1980s.

As with the FM synthesis, Yamaha secured the rights and developed from 1989 onwards, together with Stanford University, this synthesis method; the first such working synthesizer in series production in 1994 was the Yamaha VL -1. In this way, an attempt was also soon to resurrect the old analog synthesizer digitally with their sonic shortcomings as a virtual analog synthesizer again. These include the Clavia Nord Lead, Access Virus and the synthesizer of the company Waldorf. After the digital synthesizer sounds of the 1980s, it came in the 1990s to a renaissance of analog synthesizers and their sounds, especially with the advent of the techno music. Formerly almost worthless synths like the Roland TB -303 increased thereby again significantly in value.

Hybrid Synthesizer

Almost all of today's synthesizers are completely digital. They usually use special DSP blocks for sound generation, often various forms of sound synthesis can be used simultaneously.

In recent years, some so-called hybrid synthesizers have been developed that combine the DSPs with analog components, in which both a mostly digital signal such as in the Waldorf Q ( analog filter, otherwise DSP based) or a predominantly analog constructed signal (DSI Evolver, Alesis A6 Andromeda ) are possible. The concept of hybrid synthesizers dates back to the 1980s, models such as the ESQ1 combined Ensoniq short samples or additively generated waveforms with analog filters. The Yamaha SY99 could, however (see above) feed samples loaded in the FM synthesis and the resulting waveforms again subtractive process ( filter) and thus combined sampler and digital FM synthesis with subtractive sound production.

Software synthesizer

A new trend is called "native software synthesizer ". Due to the high performance of modern PCs, it is possible to perform digital sound production on unspecialized processors. There are now different for each type of synthesis software synthesizers that are simulations of known hardware synthesizer part. Also known old instruments such as Fender Rhodes piano, or the Hammond B3 organ can be simulated.

This software synthesizers are often controlled by a master keyboard, a pad controller or a knob. The problem is that they are tied to a specific operating system version and so not as durable as hardware synthesizers.

Digital sound production

Mobile synthesizer

Mobile phones have had since about 2000 such a high computing power, that they can play as a synthesizer application programs (apps ) that the classical analog and even many digital synthesizers inferior to nothing in their sound shaping. You have multiple oscillators with pulse-width- modulated numerous waveforms, frequency and amplitude modulation, detuning, envelope, delay, Exciter, Chorus and reverb effects as well as dynamic filters. Played they are preferred over MIDI files because the games is a bit tedious on a small mobile phone keypad. An example of this is the Windows Phone synthesizer ( see links).

Related Art

Vocoder

Technically related to the synthesizer vocoder is used for tonal modulation of analog instrumental sounds or noises ( carrier signal ), usually with the help of the human voice as a control signal. The dynamic and timbral characteristics of the controlling speech signal are transmitted by means of filters and control voltages to the instrumental sound, seems so to speak this or sing.

Oscillator

In electrical engineering, a synthesizer describes an electronic device for synthesis of monophonic, highly pure vibrations, such as a sawtooth, sine, triangle and square wave or generation of spikes. Such devices, also known as a function generator, used to verify electronic circuits, often of amplifiers. Since it is laboratory equipment, they have usually an extremely low noise and lying on the border of measurability distortion.

Such generators that are now realized almost exclusively with digital components, also referred to as digital oscillators.

MIDI

A small revolution in the development of the synthesizer was the development of MIDI, a simple digital serial standard interface for synthesizers. It was developed by the companies presented Roland and Sequential Circuits and 1983. It has established itself in a short time than standard industry interface. To this day, she is found in almost unchanged form in each synthesizer and allows you to connect a variety of electronic devices in a simple manner with each other. In 1991 he was with General MIDI ( GM) an extension of the standards to the sound of occupancy. Thus, for example, an oboe sound always found on the same program location. This allows you to play complete songs with the right sound assignment on GM- compliant playback devices.

Sound Module

A sound module is a sound -producing device or software module without keyboards; it is connected by MIDI or USB with the corresponding devices.

Sequencer

A sequencer controlling a different sequence ( sequence) of tones or sound events, which are generated by another device or module. Sequencer spread along with MIDI, which usually serves as a standard for data transmission. A similar function has the arpeggiator, which stores a shorter, contiguous sequence of notes that can then be played as by a key press.

Synthesizer manufacturers

In the following, an alignment known manufacturers that have shaped the development of synthesizers prevail. In brackets are areas in which the respective manufacturer has taken effect.

• Access Music Electronics ( virtual analog synthesizer, integrating hardware into software systems )
• Acxel2 ( Idarca Audio Inc, re-synthesis, synthesis and multi- multi -timbral modular systems )
• ARP Instruments (Modular Systems )
• Instruments.de anyware - (modular analog synthesizer, TINYSIZER )
• Clavia ( virtual analog synthesizer)
• Club Of The Knobs (modular analog synthesizer)
• Casio ( PD synth)
• Doepfer (modular and non-modular analog synthesizer)
• Electronic Music Studios (voltage -controlled analog synthesizer, in particular by the EMS VCS 3)
• Ensoniq ( digital synthesizers, workstations, samplers )
• Fairlight ( sample-based digital synthesizer )
• Korg (semi - modular systems, analog and digital synthesizers, workstations )
• Kurzweil ( sample-based, physical modeling and virtual analog synthesizers and digital workstations / Performance Controller )
• Moog (modular systems, analog synthesizers )
• New England Digital ( FM synthesis, digital synthesizer )
• Oberheim (multi -timbral synthesizer, analog synthesizers, expanders )
• PPG (PPG 1020 first synthesizer with digital oscillator, wavetable synthesis)
• Roland Corporation ( analog and digital synthesizers, workstations, groove boxes )
• Sequential Circuits (microprocessor -controlled synthesizer)
• Waldorf ( analog and virtual analog synthesizer)
• Yamaha ( FM synthesis, physical modeling synthesis, sample-based workstations)