Electronic Music


An introduction to hardware units

Moog Source synthesizer

Moog Source monophonice synth of 1981 had large knob to change most parameter values and a soft-membrane control panel as well as a 24-note arpeggiator and two 88-note sequencers

By Carter B. Horsley

Until the introduction of Robert Moog’s legendary Minimoog portable music synthesizer in the 1970’s, electronic music was a product generally of studios and rarely used for live performances. Early sophisticated synthesizers involved large banks of modules connected by patch cords that had to be rearranged for each different sound. Early experiments in computer music were capable of considerable complexity, but not in real-time and were the domain of a few university installations and electronic music centers primarily.

Advances in microchip technologies, of course, would bring eventually bring electronic music to the masses, but the initial advances were fairly slow in coming and each small advance was hailed as something rather revolutionary.

There are many forms of music synthesis but the initial method that became the most popular was "subtractive," that is, filters were used to cut away, or "subtract," unwanted noise generated by analog oscillators. Another module generally known as an "envelop" would shape the sound in time by providing controls for how quickly its attack would sound, how long it would sustain and how long it would take to fade away.

This was the basic configuration of the Minimoog, which offer a few different "shapes" for each of its three oscillators that could be mixed in different amounts and the third oscillator could be switched to modulate the other day. Modulation of one component by another is an important way of creating different sounds. The early portable models had very few modulators and modulation destinations, but with advances in computer technology modulation "matrixes" would become extremely complex.

The Minimoog would be challenged by some product made by Arp that also adopted the "subtractive" technique, but with slightly different components and features.

The original portable synthesizers by both Moog and Arp were monophonic, that is, could produce only one sound at a time and thus were used primarily as "lead" instruments. The first polyphonic synthesizer to gain wide popularity was the Prophet 5, which was produced by Sequential Circuits and introduced in the late 1970s. It had 5 voices and could therefore produce up to 5-note chords. Other manufacturers such as Oberheim, Yamaha and Roland, as well as Moog, would soon follow with their own polyphonic synthesizers. In addition to polyphony, these new synthesizers also had patch memories, that is, they could store all the settings of a specific sound’s parameters for instant recall, but initially not too many sounds could be so saved. One Oberheim module permitted 8 different sounds to be memorized. The first Prophet 5 could save 40 patches, although later versions could store as many as 120. The first very popular polyphonic synthesizer from Roland, the Jupiter 8, which was also one of the most beautiful with its steel case and multi-colored buttons, could store 64.

Computer memory was expensive and the initial top-of-the-line polyphonic synthesizers cost several thousand dollars at the start of the 1980s, and a fully equipped New England Digital Synclavier would cost more than $200,000 in the early 1980s, although it was an "additive" synthesizer rather than a subtractive model and it created sounds by adding together different sounds and its technology was digital rather than analog, about which more later.

By 1981, synthesizer technology became to make rapid advances. A Moog monophonic synth, the Source, shown in the photograph at the top of this article, was introduced that year with memories to store 16 different sounds and it had a 24-note arpeggiator, two 88-note sequences and a soft membrane control panel whose parameters were changed by a single, large dial, similar to that on the New England Digital Synclavier. It sold for more than $1,000.

The next year witnessed the introduction of the Rhodes Chroma, a 8-voice synthesizer with memory for 50 sounds that also used a soft membrane control panel whose parameters were changed by a single fader but it also had velocity sensitivity and 16 different configurations, or algorithms, of its components that permitted it offer not only traditional oscillator-filter-envelope routing but also to have ring modulation and several different routings for its two filters and two envelopes. It also promised to offer pressure sensitivity, which did not become widely available, but it did have computer interfaces that were quite sophisticated. The Chroma was the last synthesizer to be designed by Arp, which was taken over by CBS, which also had recently taken over Fender and Rhodes in an effort to become a major player in the music instrument business that unfortunately would not pan out. The Chroma, which had a weighted keyboard, was the most sophisticated synthesizer to date and had a list price of more than $5,000. Its 50 soft memory buttons also doubled as access to its parameters many of which had 16 functions and others of which had ranges of -64 to +64.

The Chroma’s main competition was the Prophet 5, the Roland Jupiter 8, the Oberheim OBa, and the Octave Plateau Voyetra, the latter a rack-mountable module with a very complex set of controls, many of which were hidden on "pages" that were not clearly indicated on the front panel. All of these, except for the Chroma, were not velocity sensitive, a very important feature for adding expression and nuance.

The Chroma’s dominance as the top synthesizer was short-lived, however, because of CBS’s failure to support the instrument with upgrades and, more importantly, the introduction within a year of Yamaha’s legendary DX7, an "additive" synthesizer that was the first to incorporate MIDI (Musical Instrument Digital Interface, see The City Review article). The DX7 became one of the best-selling synthesizers of all time. It was priced at only $2,000 and offered mind-boggling complexity because its sounds consisted of six oscillators, which Yamaha called "operators," that could be arranged in 32 different configurations, which Yamaha called "algorithms." It too offered a single controller, a fader, to change its parameters but its synthesis system, which was known as FM for "frequency modulation," was extremely challenging for it was not intuitive and minute differences of settings could radically change the sound, often resulting in very unpleasant and not very musical tones. Despite its complexity, however, the DX7 was capable of some very fine sounds and the "factory" sounds it came with became very popular, especially its electric piano, vibes, bells and brass sounds, so much so that it was often reported that about 90 percent of its users only used the "factory" sounds and gave up on programming their own. Each of the operators only generated sine waves, but later models from Yamaha would offer more waves and its FSIR synthesizer introduced in 1999 would have 88 algorithms and "formant" filters, about which more later.

The DX7’s popularity was due primarily to its digital sounds, its velocity sensitivity, its relatively low price, and its MIDI implementation. It also could respond to "breath" control, about which more later. Although originally most people thought MIDI would primarily be used to layer different synthesizers, it would soon revolutionize the music industry, permitting performers to record on a computer every nuance of their performance and compose for many different MIDI-equipped synthesizers.

"Digital" became a major buzz word and many manufacturers created "hybrid" machines, some that combining analog oscillators with digital filters and others combining digital oscillators with analog filters. Analog oscillators had a tendency to drift out of tune, while digital oscillators were always in tune.

Oberheim Expander synthesizer module

The Oberheim Xpander synthesizer module of the mid-1980s offered extensive modulation routings and MIDI implementation.

The last major analog synthesizer was the Oberheim Xpander, shown above, which took the classic oscillator-filter-envelop routing and adding enormous routing capabilities and new features. Most subtractive synthesizers up until the Xpander, which was a keyboard-less module that would eventually be issued with a keyboard, had one envelop to modulate the filter and another to modulate the sound’s behavior over time (the amplitude envelop, that some manufacturers termed the amplitude generator). The Xpander added three extra envelopes that could be assigned to a great variety of destinations such as the attack portion of another envelope or the rate of a LFO (low-frequency oscillator often used to create tremolo or vibrato effects). Instead of one LFO, it had five LFOs. It also had tracking generators, lags and ramps, which were simplified envelopes, and 15 different filter configurations. The Xpander had six-voice polyphony with each voice having two oscillators. The voices could be played monophonically or polyphonically and its MIDI implementation, the best to date, permitted it to play six different monophonic parts simultaneously.

The Chroma, the DX7 and the Xpander were very "deep" machines whose programming capabilities were difficult to master but capable of quite amazing sounds. A relatively simple monophonic synthesizer such as the Moog Source had 39 programmable parameters for each sound, some of which were simply on/off switches, but it was probably capable of several quadrillion distinct sounds. The Chroma, DX7 and the Xpander were a couple of quantum notches more complex.

All of these models, however, were based on relatively simple basic oscillator sounds, but in the mid-1980s Kurzweil, Roland and Korg came out with the 250, D50 and M1 synthesizers, respectively, that incorporated sampled sounds that could be added to traditional synthesizer sounds and greatly expanded the sonic palette of synthesizer players. These models would permit players to combine the sampled attack sound of a trumpet, for example, with a synthesized string sound. Their routing "architecture" was relatively simple and they were no way near as complex as the Chroma, DX7 and Xpander, but offered impressive sounds that became very popular. The Kurzweil quickly became famous for its sampled piano sounds, but the original model cost about $10,000, although Kurzweil would subsequently issue excellent rack modules for about $1,000, and then keyboards based on its V.A.S.T. architecture in its 2000, 2500 and 2600 series, all of which were very good and complex instruments.

Samplers, electronic music instruments that could record real sounds and permit them to be played back on a keyboard, started to appear in the early 1980s and popular models were developed by Emu, Ensoniq, Casio and Akai. These units, however, were limited by microchip technology and generally could only load one sound at a time and the quality was initially only 8-bit, although it soon got up to 16-bit. The high costs of memory, however, made them relatively expensive and the complexities of recording and properly editing sounds to be playable on a keyboard challenging many players giving rise to a mini-industry that provided sampled sounds on floppy disks and then compact disks.

Proteus 1 synthesizer module

The Emu Proteus/1 synthesizer module had a simple interface but very deep parameter controls and modulation and was the first in a long series of successful sample-playback modules by Emu

The Emu Proteus series of synthesizers, which began to appear in the late 1980s offered rack modules for about $800 each that not only incorporated very good samples for playback and mixing with regular synthesis sounds but also very complex modulation capabilities and 16-part multi-timbrality. In the mid-1990s, Emu expanded the series to include a very exotic and complex new type of filter that it termed "Z-plane" and which permitted morphing between different sounds. The first model was the Morpheus and it was succeeded by the Ultra-Proteus, which offered more than 100 different filters and both models represented quantum leaps in music potential from the Chroma, DX7 and Xpander. Despite their fabulous but intimidating filters, Emu would begin to tailor its newer models to specific sound categories, such as orchestral and dance, to were popular with players who wanted quick, easy and good sounds and tended not to get too involved with programming.

Sequential Circuits, Moog and Oberheim, as well as lesser known manufacturers such as Crumar, Synergy (a favorite with Wendy Carlos) and PPG, would not survive the marketing wars of the 1980s, even though Sequential Circuits would develop a vector synthesis architecture that permitted the morphing of sounds over time, an approach similar to that developed and used in the Korg Wavestation module. Both of these would permit the creation of very complex, evolving and changing sounds that were very distinctive, but not easy to program. The PPG wave synthesizer was very popular in Europe but was expensive. (It should be noted that there were numerous other manufacturers that ventured into the very high-end of the synthesizer market with instruments costing $30,000 and more, but the market at that level was very thin and dominated by Fairlight and New England Digital Synclavier, both of which eventually went out of business as computer technology rapidly advanced and made their extraordinary capabilities, especially in sampling, much less expensive.)

Korg, Roland, Yamaha and, to a lesser extent, Kurzweil, continued to roll out new models with great regularity in the late 1980s and early 1990s, but they essentially were only added more memory and a few features. The Roland D50 had been the first popular synthesizer to include effects, which greatly enhanced its sound, and subsequently virtually all new synthesizers would do the same, albeit with varying degrees of quality.

In the early 1990s, Yamaha introduced some models that featured "physical modeling" synthesis that was quite expensive but very impressive. It and Akai had introduced wind controllers for electronic music in the mid-1980s that were superb controllers, but required considerable technique that was not keyboard-oriented. The Yamaha WX7 wind controller is and may well be the instrument of choice for Darth Vader. The "physical modeling" method of synthesis was completely different from subtractive and additive methods and was very memory intensive. It, nonetheless, was capable of producing very authentic imitations of many string and wind instruments, but was notoriously difficult to program.

Korg began work on its "Oasis" synthesis architecture in the early 1990s and would incorporate some of its physical modeling capabilities in its Prophecy monophonic synthesizer in the mid-1990s. The Prophecy, which cost about $1,000, was also notable for its ribbon controller that was built into its pitch and modulation controllers and was an excellent ergonomic advance that offered players expanded expressiveness. Korg would subsequently come out with a six-voice version known as the Z-1 and also offered the Prophecy’s synthesis engine as an option on other models.

In the late 1990s, "retro" interest in analog synthesis resulted in the emergence of some new manufacturers, such as Novation and Virus, both of whom produced some very impressive and good synthesizers and another company, Waldorf, introduced models that were based in part on the discontinued PPG Wave synthesizer.

Kawai K5000S digital synthesizer

The Kawai K5000S synthesizer of the late 1990's offered incredible digital sound sculpting, a fine arpeggiator, excellent keyboard, and good group of assignable control knobs

Another company, Kawai, shook up the synthesizer world in the late 1990s with the introduction of its K5000S synthesizer, shown above, a "monster" of a digital, "additive" synthesizer that represented a couple of quantum leaps in complexity beyond virtually anything else of the market. The complexity, which included envelopes for each of 128 sine waves, for example, was eased considerably by an excellent user interface with many knobs that also happened to include a keyboard with a very fine action and a very sophisticated arpeggiator. Although it originally cost around $1,500, it was surprisingly discontinued rather quickly and available for a brief time for a "blowout" price of around $400, which was probably the synthesizer bargain of a lifetime.

Around this time, advances in personal computer technology gave rise to an explosion of interest in software synthesizers, many of which could be used as "plug-ins" to major sequencing programs like Steinberg Cubase VST 24 and Logic Gold. At the end of the Millennium, Steinberg was offering software "plug-in" programs that reproduced on the computer screen very impressive renditions of enhanced classic synthesizers such as the Minimoog, the Prophet 5 and the PPG, all with full MIDI implementation, expanded memories and street prices of only about $150.

These "plug-in" software synthesizers were quite excellent emulations of the famous synthesizers, but they required considerable memory for non-glitch operation. However, memory prices by this time had become quite reasonable and the prospect for purchasers of new computers was that it was beginning to be possible to envision electronic musicians using their personal computers as quite complete Digital Audio Workstations that could incorporate several different software synthesizers with lots of polyphony, 24-bit mixing and recording and lots of special effects, all inside the computer. As spectacular as these advances have been, however, adjusting parameters on the software synths is not as easy as twirling a knob on an old-fashioned, external, free-standing synthesizer or module, at least for a not insubstantial number of musicians.

Major manufacturers such as Yamaha and Korg introduced sound cards for computers that are the equivalent of large digital mixers at a fraction of the cost. For many old hands, the love affair with their instruments will be hard to replace, but they also have to be enticed by the fantastic ability to use instruments that perhaps they never could have afforded originally, or are unable to find in good condition regardless of cost.

This brief overview of the highlights of the past generation’s synthesizers has omitted many models and it should be noted that almost all of them had their own distinct qualities. While most could produce quite similar basic sounds such as bass, strings, horns and the like, many had distinctive sounds that reflected different filters or other features. The Casio CZ-101, for example, shown below, was introduced in the mid-1980s and offered 8-part envelopes rather than the traditional four-parts of Moogs, Oberheims and Prophets and its digital sound was very impressive at a cost of around $450 originally.

Casio CZ 101 digital synthesizer

The Casio CZ101 was introduced not too long after the famous Yamaha DX7 at about a quarter of its price and with more complex envelopes for shaping the duration characteristics of a sound. It was a relatively simple digital synthesizer but capable of some quite evocative sounds even though it was not velocity-sensitive.

Clearly, there are many choices.

For those who are thrilled with programming exotic sounds, the Kawai K5000S, the Yamaha FS1R, the Rhodes Chroma, and the Oberheim Xpander stand out, although they are not easy to find. Each of these instruments can keep an expert programmer busy for a lifetime.

An ideal "rig" should have two synths that have keyboards, since one may develop problems. There are keyboard controllers available but it makes sense to have at least one major instrument that can serve as the main controller with a good arpeggiator, split keyboard zones and multi-timbrality. Roland, Yamaha, Korg and Kurzweil all have major keyboards that will serve well, although some are also loaded with sequencers, which may not be necessary for many players who use computers for sequencing and other music uses, such as software synthesizers.

A good rack module, like the Roland XV-5080, offers an enormous inventory of sounds that is expandable and a very good user interface. Its architecture is based essentially on the earlier Roland JV-1080.

The notion of "plug-in" software synthesizers is wonderful, but there are some drawbacks. They require very powerful personal computers with lots of memory and many have annoying copy protection implementations that can be quite a nuisance and they only work within certain software programs, some of which are tauntingly complex, albeit fantastic.

While it is very tempting to try to squeeze every last once out of the personal computer and create and record 128-part compositions within them with only a single "outboard" keyboard, it is also an approach that is not always conducive to inspirational fiddling with knobs and faders and buttons. Some people, of course, have great hand-eye-mouse coordination and can remember keyboard alternative function codes easily for many different programs, but such virtuosi are perhaps even rarer than old-fashioned hardware virtuosi. (This article has avoided discussion of alternative controllers such as wired fingers and shoes, brain-wave attachments, movement sensors and the like, all of which are fascinating and exciting, but are beyond the beginner stage, to put it mildly.)

Even the seemingly simplest of synthesizers, such as a Roland SH-01, a Casio CZ 101, or a Minimoog can take a long time to master and begin to explore its sonic potential, which is vast. Synthesizers with more advanced features can take years to truly begin to master. For many users, the virtually infinite sonic possibilities of most synthesizers is a Pandora’s Box, for it is easy to get delightful lost in shaping sounds and that time may take away from other basics such as creating melodies and mastering a recording. Are you a musician or a technician?

Give someone a synthesizer and they will become a sound programmer, a recording engineer, a composer, a performer and hopefully a musician.

There are presumably some wizards out there who can listen to any electronic recording and pick out which synthesizers are playing which parts and perhaps even discern what modulation controllers are being used. Such wizards, needless to say, are very rare, as are true synthesizer virtuosi, which is not to suggest that there are not a great many musicians with fabulous chops who make music with synthesizers, but usually they are using conventional sounds and not utilizing all of the instruments’ potential.

In recent years, some of the more bizarre, and interesting, sounds that created with synthesizers come from "groove boxes," in which the player/DJ samples and remixes other sounds/recordings into loops and is able to come up with unusual syncopations. The world of manipulated, sampled sounds is intriguing and vast and worthy of its own article.


Harmonycentral.com has good information on various synthesizers

Synthzone.com also has good information on various synthesizers

Roland has a good website at rolandus.com


Home Page of The City Review