Yamaha DX7

The Yamaha DX7 is a FM Digital Synthesizer manufactured by the Yamaha Corporation from 1983 to 1986. It was the first commercially successful digital synthesizer. Its distinctive sound can be heard on many recordings, especially pop music from the 1980s. The DX7 was the moderately priced model of the DX series of FM/PM keyboards that included DX9, the smaller DX100, DX11, and DX21 and the larger DX1 and DX5. It is often claimed that over 160,000 DX7s were made, and it remains second best-selling synthesizer of all time, after Korg M1 (1988, 250,000 units sold).

Tone generation in the DX7 is based on linear frequency modulation synthesis (FM), based on research by John Chowning at Stanford University. The DX7 was known for precision and flexibility of its bright, digital sounds, which were much clearer than those of the analog synthesizers that preceded it. The DX7 is well known for its electric piano, bells, and other "struck" and "plucked" sounds which emphasize complex attack transients. It is capable of 16-note polyphony. While the instrument is monotimbral, it is notable how the sound of a single DX7 patch can change either subtly or wildly along the length of the keyboard or when played with different velocities. The DX7 features 32 algorithms, each being a different arrangement of its six sine wave Operators, allowing for a great deal of programming flexibility.

Programming

The Yamaha DX7 earned a reputation of being difficult to program, primarily due to players being accustomed to the traditional synthesizer architecture of analog oscillators, filters, LFO generators, etc. While other early digital synths used wavetable synthesis, this required considerable memory, which was simply cost-prohibitive in 1983 when the DX7 was introduced. To get around this issue, the DX7 was built upon entirely different sound engine design, consisting of a combination of "carrier" sine wave oscillators and "modulator" oscillators that can be interconnected in numerous ways, and being organized into 32 most useful "algorithms". This resulted in the DX7 being demonstrably more capable than other devices in its price range. As such, programming the synthesizer was predictably more complicated, especially given the limitations of the instrument's user interface. Those who made effort to become proficient in programming the DX7 however, were rewarded with the full range of the instrument's expansive soundscape. Whereas programming was initially possible only via front panel buttons and sliders, numerous software editors have since become available that allow the user to view and manipulate all parameters in real time.

Voices (sounds) can be stored into the 32-voice RAM internal memory, or accessed via a corresponding 32-voice DX7 RAM cartridge, inserted into a front panel access door/port. All internal voices can be edited and overwritten by the user, as with the Korg M1 and Roland D-50. The DX7 originally shipped with two pre-programmed ROM cartridges, each containing two banks of 32 voices each, which gave the buyer 128 factory voices. Modern software editors make it possible to obtain sound banks from online sources and load them straight into the DX7 via MIDI.

MIDI

The original DX7 included MIDI ports, but was released shortly before the specification was completed. As a result, its MIDI implementation is quite modest - it only transmits information on MIDI channel 1, it can receive information on any one of the sixteen MIDI channels at a time, but lacks the OMNI feature that enabled later DXs in the series to receive on all MIDI channels simultaneously. Very early DX7s manufactured in 1983 were distinctive for not having "MIDI Channel" inscribed next to the button that opens this function (button 8). This missing label was corrected early in the production run.

Additionally, the maximum MIDI velocity value that the DX7 will transmit is 100 (of the 127 maximum value defined by the standard). The DX7 will however, respond to the full range of velocity values when sent from an outside MIDI source. This means that when using the original DX7 as a MIDI controller to play external sound modules, the patches on these modules must be adjusted to be more sensitive to velocity. It also means that when playing the DX7's own sounds using an external MIDI controller or sequencer, the velocity values should be rescaled before the input to the DX7, or the DX7 patches would need to be adjusted to be less sensitive to velocity.

DX7 Mark II models resolved these deficiencies and were equipped with full MIDI implementation, including the ability to send and receive on any or all of 16 channels, send program change commands, controllers commands (total of 103 parameters can be assigned to any controller), and SysEx (system exclusive) messages, thus making them quite useful as a MIDI controllers for other synths and sound modules.

Variants

The original DX7 featured a brown case with plastic membrane film buttons, and was produced from 1983 to 1986. Three improved DX7 II models were released between 1987 and 1989, all of which featured updated internal circuitry with improved sound quality (from 12-bit to 16-bit), and a more aesthetically pleasing black metal case with conventional buttons and larger sliders:

• DX7 II D: added bi-timbrality, increased the internal patch memory, and added the ability to transmit on any one of 16 MIDI channels
• DX7 II FD, later also branded as DX7 II+: added a floppy disk drive (3.5" 720 kB DS/DD)
• DX7s, sometimes called DX7 II S: This is the single-timbre (hence the s) variant of the DX7 II series, featuring the same essential functionality of the original DX7 but with the improved 16-bit sound engine of the "II" models, and double the internal memory (64 patches vs. 32). Other notable improvements include a new Performance mode, Unison mode (for fatter analog-type sounds), and more streamlined editing due to direct access to operators via front panel buttons.

Third-party support for the DX7 also flourished in the 1980s, including Grey Matter Response's E! expansion board, which added sequencer functions to the DX7 II keyboard, increased patch memory, and featured a vastly improved MIDI implementation for the original DX7. Eventually, Yamaha began to release DX7 II FDs with the E! built in. This led to a shortage of non-E! models of the II FD, to which Yamaha responded by upgrading II Ds with disk drives and stencilling the existing case to have the new name DX7 II+; these are equivalent to the II FD.[1]

The upgrade to 16-bit digital-to-analog converters helped to solve one of the original DX7's shortcomings: noisy output. The instrument's 12-bit DAC's generated a fair amount of hiss, and some users resorted to using a noise gate in the signal path to quiet the unit.

Yamaha wisely designed the DX7 II series such that voices produced on the original DX7 were compatible with the new models. This allowed users to enjoy the benefit of the increased resolution and fidelity of the new 16-bit system with existing DX7 patches. This meant that the DX7 II maintained backward compatibility with the vast base of existing DX7 sounds, which amounted to a major selling point for the new units.

In 1988, in celebration of the company's 100-year anniversary, Yamaha released the DX7 II Centennial. It was a DX7 II FD that featured a silver case, gold painted buttons and sliders, and 76 glow-in-the-dark keys. Only 100 were produced, and they were offered at $3995 USD.

Rack mount and desktop

Yamaha's TX7 and the TF1 are essentially keyboard-less versions of the original DX7, both of which share compatibility with the DX7 sound patches and produce sound in exactly the same way as the DX7.

The TX7 is configured as a standalone desktop unit with a slanted front control panel and LCD display. It essentially provides the core of a DX7, without the on board editing interface. Editing is accomplished externally via MIDI, using a DX7, PR7 programming keyboard, or computer.

The TF1 is a small vertical module that is essentially a DX7 condensed into a single circuit board. The TF1 module is designed to be inserted into a special chassis which could accommodate up to 8 TF1s. This chassis, fully populated with 8 TF1s, was sold as the TX816. This modular concept was also offered as the TX216 (with two sound modules), which could be customized by inserting additional TF1 modules, purchased separately. Both the TX216 and the TX816 were capable of multitimbral operation, but only when used with a sequencer with multiple MIDI outputs, such as Yamaha's QX1.

Another relative of the DX7 family includes the TX802. The TX802 is effectively a rack mountable DX7 II with 8-part multitimbrality. Its rather confined user interface effectively necessitates an external hardware or software editor, but otherwise provides the power and flexibility of a DX7 II in a compact format.

Notable sounds (patches)

Electric piano emulation

The DX7 Rhodes (also known as DX Rhodes, FM Rhodes, FM E. Piano, or Digital Rhodes) is a Fender Rhodes emulation, which originated from the "E. Piano 1" patch on the Yamaha DX7 and TX-series rack mountable synthesizers. This distinctive sound, while hardly an exacting facsimile of the ever-popular Fender Rhodes electric piano, was nevertheless sufficiently reminiscent to evolve into what is arguably the single sound with which the DX7 is most commonly identified. Meanwhile, the first true digital Rhodes patches weren't available until the introduction of the Rhodes MK-80 piano in 1987, following Roland's purchase of the Rhodes brand.

The DX7 II (and DX7S) provided a distinctive, bright, overtone-rich evolution of the "E. Piano 1" sound as a preset. On the DX7 II this sound became known as "Fulltines."

Because the factory "E. Piano 1" DX7 preset only faintly resembled a real Rhodes Piano, and the subsequent "Fulltines" even less so, devotees of real vintage electric pianos often express their distaste for the DX7 Rhodes sound. Its strong presence in synthesizer-heavy music, especially pop ballads during the 1980s, has led to the sound being labeled a cliché. Notable pop songs that use this preset are: After All by Al Jarreau, Here and Now by Luther Vandross, and Hard Habit to Break by Chicago, among others.

Variations of the DX7 Rhodes sound were manipulated by individual artists and programmers as well as other synth manufacturers. Though not always produced using Yamaha DX/TX equipment or FM synthesis, the family of sounds derived from Yamaha's "Fulltines" became ubiquitous in popular music from 1984 through the early 1990s. Many modern synthesizers, digital pianos, and home keyboards by Yamaha and others include some kind of 'FM electric piano' patch that imitate the DX7 Rhodes sound, although nowadays it originates from samples or wavetable synthesis rather than true FM synthesis . In the 1990s, improvements in sampling technology decreased emphasis on synthesized sound in popular music, followed by a resurgence of interest in earlier analog synthesizers led to this iconic sound falling out of favor.

Marimba emulation

The DX7 Marimba preset was also used extensively in 1980s electronic and commercial music. As with the E. Piano 1 preset, traditionalists typically react negatively to the DX7's "hard mallet" Marimba sound, instead preferring the more mellower "yarn-wound" mallet sound used by concert Marimbists. The DX7 is capable of producing such a sound, but the difficulty of FM synthesis programming, combined with the immediacy of the stock DX7 sounds, usually meant that players performed and recorded with the sounds available at their fingertips. This being the case, factory DX7 sounds flourished in recorded music in the 1980s. Two songs that are readily identified with the DX Marimba sound are Sting's "Love Is the Seventh Wave" and composer Harold Faltermeyer's "Axel F."

Electric bass

The DX7's factory-preset patch "Bass 1" has also been extensively used as-is in recorded music, including famous examples such as "Take on Me" by A-ha, or "Broken Wings" by Mr. Mister.

Software emulation

Native Instruments has developed a popular software synthesizer, the FM8 (2006) (previously the FM7 2001–2006), that emulates the DX7's digital circuitry and can load original DX7 patches. It also improves upon the FM7 in that it can also load patches from Yamaha's 4-operator FM synths, including the TX81z, which was the first FM synth to allow non-sine wave operators.

Bristol Synthesiser among other vintage synthesizers can emulate the DX-7 under Linux. The Bristol emulator works with OSS, ALSA and JACK sound systems.

CSound also has opcodes for producing DX7 sounds.

Propellerhead has a Rack Extension (PX7) emulating the DX7 in the Reason environment. Original DX7 patches can be converted to the PX7 format.

Program piracy

Since the DX7 allows users to program different patches, it is possible to copy others' patches for use in one's own DX7. As such, skilled programmers often go to great lengths to protect their sounds from being copied. Some even resort to the inclusion of alien keyboard scalings or nonsensical characters in the program name to ID their work.

Evolution of FM synthesis

The most advanced keyboard FM synthesizers from Yamaha were the SY77, its rack-mounted equivalent, the TG77, and their successor, the SY99. These SY/TG devices developed the familiar 6-operator FM of the DX7 series into AFM (Advanced Frequency Modulation) by adding more algorithms, freely assignable feedback loops (up to 3), additional waveforms, and more. The series also added filters, fully controllable panning (not just the mono of the DX7/DX7s or static panning of the DX7 II), AWM (Advanced Wave Memory) for playing back PCM samples and using them to modulate AFM instruments, and on-board effects, including reverb and chorus. The SY77 featured 61 keys and a 3.5" floppy drive to save patches, whereas the SY99 had a larger 76-key keyboard, the ability to load the user's own samples to RAM, and improved effects. The SY99 is widely considered as Yamaha's most advanced keyboard-based FM synthesizer.

Perhaps the ultimate FM synthesizer ever released however, was Yamaha's rack-mounted FS1R in 1998, with the long-awaited 8 operators, a highly enhanced 88-algorithm engine, the unique feature of formant shaping, 8 waveforms with various parameters that can be customised, and other rare and valuable features. Unfortunately, some feel that it retained the main perceived flaw of FM synths, the difficulty of programming, particularly because as a rack-mounted unit, it required an external software-based editor to exploit its full capabilities. By that time, FM synthesis was falling out of favour, so the FS1R had a short production span. Unlike the TG/SY77/99, it did not feature AWM.

The DX7 family remains popular to the present day, as does the innovative FM technology that it pioneered. Since the introduction of the DX7, FM synthesis continues to distinguish itself for is its ability to create unique new sounds, rather than just the emulation of existing instruments. The latter was one of its main selling-points in the early years of FM but also led to limited exploration of its possibilities as many players simply used built-in presets that emulated other instruments. The evolution of FM synthesis continues in modern devices (mostly software-based, such as FM8), which commonly employ additional synth engines, more waveforms than the DX7's basic sine wave, and advanced filtering.

External links

• DX7 page on Vintage Synth Museum A photograph, samples of DX7 sounds and a few technical details.
• Dave Benson's DX7 Page A huge DX7 resource, with service manuals, circuit diagrams, and auxiliary software.
• Roundsquare - The home of DX7 Librarian, a DX7 interface for Mac OS X.
• Les Miserables Keyboard Research Blog entry explaining use of DX7 and its patches in the musical Les Misérables.
• owners manual