A digital synthesizer is a synthesizer that uses digital signal processing (DSP) techniques to make musical sounds. Electronic keyboards make music through sound waves.

History[link]

The very earliest digital synthesis experiments were made with general-purpose computers, as part of academic research into sound generation. In 1975, the Japanese company Yamaha licensed the algorithms for frequency modulation synthesis (FM synthesis) from John Chowning, who had experimented with it at Stanford University since 1971.^[1] Yamaha's engineers began adapting Chowning's algorithm for use in a commercial digital synthesizer, adding improvements such as the "key scaling" method to avoid the introduction of distortion that normally occurred in analog systems during frequency modulation, though it would take several years before Yamaha release their FM digital synthesizers.^[2]

Early commercial digital synthesizers used simple hard-wired digital circuitry to implement techniques such as additive synthesis and FM synthesis, becoming commercially available in the late 1970s. Other techniques, such as wavetable synthesis and physical modeling, only became possible with the advent of high-speed microprocessor and digital signal processing technology. Two of the earliest commercial digital synthesizers were the Fairlight CMI, introduced in 1979, and the New England Digital Synclavier II. The Fairlight CMI was the first sampling synthesizer, while the Synclavier was originally an FM synthesizer, not adding sampling synthesis until the 1980s. The Fairlight CMI and the Synclavier were both expensive systems, retailing for more than $20,000 in the early 1980s.

In 1980, Yamaha eventually released the first FM digital synthesizer, the Yamaha GS-1, but at an expensive retail price of $16,000.^[3] The cost of digital synthesizers soon began falling rapidly in the early 1980s. E-mu Systems introduced the Emulator sampling synthesizer in 1982 at a retail price of $7,900. Although not as flexible or powerful as either the Fairlight CMI or the Synclavier, its lower cost and portability made it popular.

Introduced in 1983, the Yamaha DX7 was an early all digital synthesizer that obtained relatively broad commercial success. It used FM synthesis and, although it was incapable of the sampling synthesis of the Fairlight CMI, its price was around $2,000, putting it within range of a much larger number of musicians.^[4] The DX-7 was also known for its "key scaling" method to avoid distortion and for its recognizable bright tonalities that was partly due to an overachieving sampling rate of 57 kHz.^[5] It became indispensable to many music artists of the 1980s,^[6] and would become one of the best-selling synthesizers of all time.^[1]

In 1981, one of the first comparatively affordable sampler synthesizers was released: the E-mu Emulator. It was not the first sampler, but in comparison to the previous digital samplers, it was much cheaper.

In 1987, Roland released an important syntheizer: the D-50. This popular synth used a combination of short samples and digital oscillators. Roland called this Linear Arithmetic (LA) synthesis. This keyboard has some very recognisable preset sounds, such as the Pizzagogo sound used on Enya's "Orinoco Flow."

It became feasible to include high quality samples of existing instruments as opposed to synthesizing them. Many popular synthesizers are not synthesizers in the classic definition of the word. They playback samples stored in their memory. They still include options to shape the sounds through use of envelopes, LFOs, filters and effects (such as reverb.) The Yamaga Motif and Roland Fantom series of keyboards are typical examples of this type. They are sometimes called ROMplers.

As there was still an interest in analog synthesizers, and with the increase of computing power, another type of synthesizer was born - the analog modeling (or "virtual analog") synthesizer. These used computing power to simulate traditional analog waveforms and circuitry such as envelopes and filters. One example of this type of synthesizer was the Nord Lead.

With the addition of sophisticated sequencers onboard the workstation synthesizer was born. They include a multi-track sequencer. They can often record and playback samples, and full audio tracks, so could be used to record an entire song. The Korg M1 is an example of an early workstation synthesizer. They are usually ROMplers, to give a wide variety of realistic instrument and other sounds such as drums, string instruments and wind instruments along with popular keyboard instrument sounds such as electric pianos and organs.

With modern processing power and memory, some synthesizer has been produced that offer a variety of synthesis options. The Korg Oasys was an example of including multiple synthesizers in the same unit.

Some digital synthesizers now exist in the form of "softsynth" software that synthesizes sound using conventional PC hardware, though they require careful programming and a fast CPU to get the same latency response as their dedicated equivalents. In order to reduce latency, some professional sound card manufacturers have developed specialized digital signal processing hardware. Dedicated digital synthesizers frequently have the advantage of onboard accessibility, with switchable front panel controls to peruse their functions, whereas software synthesizers trump their dedicated counterparts with their additional functionality, against the handicap of a mouse-driven control system.

With focus on performance-oriented keyboards and digital computer technology, manufacturers of commercial electronic instruments created some of the earliest digital synthesizers for studio and experimental use with computers being able to handle built-in sound synthesis algorithms.^[7]

Analog vs. digital[link]

The main difference is that a digital synthesizer uses digital processors and analog synthesizers use analog circuitry. A digital synthesizer is basically a computer with (often) a piano-keyboard and a Lcd as an interface. An analog synthesizer is made up of sound-generating circuitry and modulators. Because computer technology is rapidly advancing it is often possible to offer more features in a digital synthesizer than in an analog synthesizer at a given price. However, both technologies have their own merit. Some forms of synthesis, like, for instance, sampling and additive synthesis are not feasible in analog synthesizers, while on the other hand, many musicians prefer the character of analog synthesizers over their digital equivalent.

Bands using digital synth[link]

The New Wave era of the 1980s first brought the digital synthesizer to the public ear. Bands like Talking Heads and Duran Duran used the digitally made sounds on some of their most popular albums. Other more pop inspired bands like Hall & Oates began incorporating the digital synthesizer into their sound in the 1980s. Through breakthroughs in technology in the 1990s almost every synthesizer now created has DSP.

Early digital synth models[link]

One of the first well known models is the made by the Korg company. Now with dozens of models, they have revolutionized digital synth creation. Bands like The Cure and Queen have used such models as the Korg M1. Another brand of popular digital synthesizer is Casio. Such artists as Moby began using the Casio CZ-101 at an early age of production.^[8]

Digital synthesis[link]

Working more or less the same way, every digital synthesizer is seemingly like a computer. At a steady sample rate, digital synthesis produces a stream of numbers. Sound from speakers is then produced by a conversion to analog form. Through signal generation, voice and instrument-level processing, a signal flow is created and controlled either by MIDI capabilities or voice and instrument-level controls.^[9]

References[link]

External links[link]

• Vintage Synth Explorer, a great resource on vintage analog and digital hardware synthesizers.
• Psycle, a freely downloadable modular software synthesizer and sequencer/tracker (open source and totally free)
• Buzz, a freely downloadable modular software synthesizer (gratis but proprietary)