|Price||Approx. US$ 2000|
|Oscillator||6 sine wave operators per voice, 32 Algorithms|
|Synthesis type||Digital Linear Frequency Modulation|
|Attenuator||1 pitch envelope & 6 amplitude generators per voice|
|Memory||32 patches in RAM (battery backup); Front panel ROM/RAM cartridge port|
YM21280 (OPS) Operator chip
|Keyboard||61-note with velocity
and aftertouch sensitivity
|Left-hand control||pitch-bend and modulation wheels|
|External control||MIDI In/Out/Thru, Foot Controller x2, Foot Switch x2, Breath Controller|
The Yamaha DX7 is a phase modulation based (marketed as frequency modulation) 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 the larger and more elaborate DX1 and DX5; the feature-reduced DX9; and the smaller and not directly compatible DX100, DX11, and DX21. Over 200,000 of the original DX7 were made, and it remains one of the best-selling synthesizers of all time.
Tone generation in the DX7 is based on linear phase modulation synthesis, officially branded as frequency modulation (FM), which was developed based on research by John Chowning at Stanford University. This uses multiple sine wave oscillators, which can modulate each other in various configurations offered as 32 "algorithms", thus generating a wide variety of possible harmonic and inharmonic spectra. The DX7 was known for the precision and flexibility of its bright, digital sounds, which could be clearer and less linear than those of the subtractive 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. Phase modulation as used in this and later synthesisers is capable of generating a wide range of both imitative and purely synthetic sounds.
The DX7 is capable of 16-note polyphony. Although it is monotimbral, the manner in which 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 can make it sound multitimbral.
Voices can be programmed by a user, and stored into a 32-voice RAM internal memory, or corresponding 32-voice DX7 RAM cartridge inserted into a front panel access door/port. Pre-programmed ROM cartridges could also be inserted here and the original DX7 shipped with two of these cartridges with two banks of 32 voices (sounds) each, for a total of 128 voices available. Several computer applications exist for various operating systems (Atari, Mac OS, and Windows) that can enable a user to load different presets into the keyboard from a computer via MIDI; most computer based midi recording software can also load to or save from the DX7.
The DX7 includes MIDI ports, but was released shortly before the specification was completed. Thus, its MIDI implementation is quite modest, It only transmits information on MIDI channel 1 and, although it can receive information on any one of the sixteen MIDI channels at a single time, it 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 lack of marking was corrected by 1984.
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 DX7 as a MIDI controller to play external sound modules, the patches on these modules will have to 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 will have to be rescaled before input to the DX7, or the DX7 patches would have to be adjusted to be less sensitive to velocity.
Three improved "DX7 II" models were released between 1987 and 1989, all of which featured updated internal circuitry and a restyled case. These were the DX7 IID, which improved sound quality from 12-bit to 16-bit, increased the internal patch memory and allowed bi-timbrality; the DX7 IIFD, which was identical to the DX7 IID except that it also had a floppy disk drive; and the DX7S, which had improved sound quality and the updated case, but otherwise had the same essential functionality of the original DX7 and in that sense, was its true successor. Third-party products for the DX7 also flourished in the 1980s, including Grey Matter Response's E! expansion board, which added sequencer functions to the DX7II keyboard, and increased patch memory and a vastly improved MIDI implementation in the original DX7. DX7 IIs could transmit and receive on any one of 16 MIDI channels at a time. The DX7 family remains popular to this day with many recording and performing artists.
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 would put a noise gate in its signal path to quiet the unit when it wasn't playing.
Yamaha wisely designed the DX7 II series so that voices produced on the original DX7 were 100% compatible with the new "II" models, which allowed users to immediately experience improved sound quality from existing DX7 patches via the increased resolution and fidelity of the new 16-bit system. Further, this meant that DX7 II owners had access to a vast base of thousands 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 with a silver case, gold painted buttons and sliders, and 76 glow-in-the-dark keys. Only 100 were made and they were priced at US$3995.
Rack mount and desktop
The TX7 and the TF1 are keyboardless versions of the original DX7, both of which are binary-compatible with the DX7 patches, and produce sound in exactly the same way as the DX7. The TX7 is in a desktop case with a slanted front, which was not designed to be rack mounted. The TF1 is in a small vertical form factor, designed to be inserted into a special chassis, called the Yamaha MIDI Rack Frame (MFR) which could accommodate up to 8 TF1s. This chassis was sold fully populated with 8 TF1s as the TX816. A reduced version with just 2 TF1s was sold as the TX216, and additional TF1s could be purchased separately and added as required, up to the full 8 making it a TX816.
The Yamaha TX802 was the rack-mounted expander of the DX7 II. The TX802 is a 2-unit high synthesiser with up to 8 multi-timbral parts. Each of the 8 parts can be assigned to its own MIDI channel and output, or the TX802 retains the ability to function as a single 16-note synth on a single channel if desired; intermediate combinations are equally possible.
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 originally produced by the "E. Piano 1" patch on the Yamaha DX7 (and TX-series rackmount) line of synthesizers.
This distinctive, fresh sound, while by no means an exact duplicate of the ever-popular Fender Rhodes electric piano, was nevertheless very reminiscent of it and has become, arguably, the single sound with which the DX7 is most identified. This sound was subsequently edited and expanded upon to produce the now-famous DX7 Rhodes sound.
DX7 II (and DX7S) released in 1987 made a distinctive, bright, overtone-rich version of the "E. Piano 1" sound available as a preset. On the DX7 II this sound became known as "Fulltines."
Variations of the DX7 Rhodes sound were produced by individual artists and programmers, as well as manufacturers of other synthesizers. Though not always produced on Yamaha DX/TX equipment or using FM synthesis, the family of sounds based on Yamaha's "Fulltines" became ubiquitous in popular music from 1984 through the early 1990s. Most synthesizers and home keyboards included an "electric piano" patch that imitated the DX7 Rhodes sound. In the 1990s, improvements in sampling technology, decreased emphasis on synthesized sound in popular music, and a resurgence of interest in vintage keyboard instruments led to the sound falling out of favor.
Because the "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 popular music, especially pop ballads, during the 1980s has led to the sound being labeled a cliché.
The DX7 Marimba preset was also used extensively in 1980s electronic and commercial music. In a similar fashion to the E. Piano 1 preset, percussionists typically react negatively to this "hard mallet" version of a Marimba sound, instead preferring the more mellow, round and warm "yarn-wound" mallet sound used by concert Marimbists. The DX7 is easily 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 they had at their fingertips; thus the stock DX7 sounds flourished in recorded music in the 1980s.
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 on its predecessor 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.
CSound also has opcodes for producing DX7 sounds.
Korg Kronos:- The MOD‐7 EXi of the Korg Kronos and Kronos X can load sounds created for the vintage DX7. Once loaded, you can bring these vintage sounds up to date using all of the MOD‐7’s unique features, layer them with other EXi, and process them with KARMA and KRONOS' effects. The conversion works by reading DX7/DX9 .SYX format System Exclusive files. N.B. In order to load a file, the file must contain a complete bank of 32 DX7 sounds. Files with only a single sound cannot be loaded. 
Since the DX7 allows users to program different tones, it is possible to copy someone else's synthetic sound for use in your own piece. Skilled programmers would go to great lengths to protect their sounds from copying.
"Various DX7 programmers have told a person that they "bury" "useless" data in their sounds so that I can prove ownership later. Sometimes the data is obvious, like weird keyboard scalings on inaudible operators, and sometimes it's not, like nonsense characters in a program name."—
- The sound of one chip clapping: Yamaha and FM synthesis, Robert Johnstone
- Holmes, Thom (2008). "Early Computer Music". Electronic and experimental music: technology, music, and culture (3rd ed.). Taylor & Francis. p. 257. ISBN 0415957818. Retrieved 2011-06-04.
- "Three Yamaha products that reshaped the industry mark 20th anniversary". Music Trades. February 1, 2004.
- ESSENTIAL DX7 Patches
- O'Reilly - Fee, Fi, Fo, FM: Explore the World of FM Synthesis
- Korg Kronos Parameter Guide Page 339 : http://www.korg.co.uk/downloads/kronos/support/KRONOS_Param_Guide_E4.pdf
- Cox, C and D Warner. (2006). Audio Culture: Readings in Modern Music. New York: The Continuum Publishing Group Inc. ISBN 0-8264-1615-2
- 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.
- Yamaha DX7 Resource Centre - A site dedicated mainly to the mark 1 DX7 (formerly www.thedx7.co.uk, now re-hosted)
- welcome at the DX1 world - all about the flagship of Yamaha DX series: the Yamaha DX1!
- Roundsquare - The home of DX7 Librarian, the ultimate 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