Yamaha DX7

Synthesis engine

Tone generation in the DX7 is based on frequency modulation synthesis, which was developed based upon research by/licensed from 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. Yamaha's implementation used DDS oscillators based on linear phase modulation, allowing improved precision and stability. 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, which most analog synthesizers of the time could not produce. Phase modulation as used in this and later synthesisers is capable of generating a wide range of both imitative and purely synthetic sounds.

Programming

The DX7's "voices" (synthesizer sounds) can be programmed by the user, and stored into a 32-voice RAM internal memory, or corresponding 32-voice DX7 RAM cartridge inserted into a port on the front of the unit. Pre-programmed ROM cartridges could also be inserted, and the original DX7 shipped with two of these cartridges with two banks of 32 voices each, for a total of 128 voices available. Several computer applications were available for various operating systems (Atari, Mac OS, and Windows) that could enable a user to load different presets into the keyboard from a computer via MIDI; most computer-based MIDI recording software could also load to or save from the DX7.

Because of the complexity of FM synthesis, and the almost limitless possibilities of sounds, many users considered the DX7 difficult to program. A particular challenge was that Yamaha's DX envelopes were very different than the Attack, Decay, Sustain and Release (ADSR envelope) methods used to create sounds in older synths, familiar to most synth players. Another difficulty was that programming required the manual entry of numbers for parameter values, rather than the simple turning of a knob. As a result, many musicians did not get far with programming and instead tended use Yamaha's preset voices. However, a few musicians who were skilled at programming the DX7 found employment creating new DX7 sounds for other bands, creating the "synthesizer programmer" as a new entry in music production credits.

Breath controller

The Yamaha DX7 came with a minijack connection for an optional breath controller which sensed the air pressure inside the player's mouth and sent an analog output voltage to the DX7. The Yamaha BC1 breath controller, first developed for the Yamaha CS01 analog synth but released in 1983 alongside the DX7, was gripped by the teeth of the player while the later BC2 and BC3 were supported at mouth level by a headset. With one of these, the player could use breath pressure to modulate vibrato, tremolo, dynamics, harmonic "brilliance" or any other programmable value in the DX7. The breath controller allowed the DX7 to be used to produce sounds similar to a wind instrument but with a piano keyboard for note selection. Many of the preset Yamaha voices allowed for breath-controlled modulation, and such modulation could be programmed into any other voice. However, pop musicians performing on stage did not usually want to put a breath controller in their mouth, for visual reasons. Yamaha also produced the WX series of dedicated wind controllers which emulated familiar wind instruments.

MIDI

The DX7 includes MIDI ports, but it was released shortly before the specification was completed, and indeed, MIDI was added very late in its development. Thus, its MIDI implementation is quite modest; It only transmits information on MIDI channel 1 and, although it can be set to receive information on any one of the sixteen MIDI channels, it lacks the Omni feature of the MIDI standard that enabled later MIDI-equipped instruments, including ones by Yamaha, to receive on any of the 16 MIDI channels simultaneously.

Additionally, the maximum MIDI velocity value that the DX7 will transmit is limited to approximately 100 (of the maximal 127 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.

Upgrades

Yamaha released an updated ROM titled the Special Edition ROM (SER) that added oft-missed features such as the ability to choose the output MIDI channel, the ability to store function data (settings for pitch bend, portamento modulation, etc.) per-voice rather than just globally as in the original, and other frequently desired enhancements. Moreover, third-party upgrades for the DX7 flourished in the 1980s, most based upon upgrading the firmware albeit with a wider range of features than Yamaha's official SER. These included SuperMax and the most famous, Grey Matter Response's E! expansion board, which added increased patch memory and a vastly improved MIDI implementation to the original DX7.

Modules

The TX7 and the TF1 are keyboardless versions of the original DX7, both of which are exactly compatible with original 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 modules changed function memory (for pitch bend settings, aftertouch, and so on) to be per-voice rather than global.

Mark II

Three improved models classed as the DX7 II family were released between 1987 and 1989, all of which featured updated internal circuitry and a restyled case. These were, in ascending order of number of features:

Yamaha 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 access a huge library of existing voices as well as the new programming possibilities and improved DAC resolution of the II models. Grey Matter Response released an E! for the DX7 II family, which, among other features, added 8-part multitimbrality and sequencing functions to these synthesisers.

In 1987, in celebration of the company's 100-year anniversary, Yamaha released the DX7 II Centennial. This was a DX7 II FD with a silver case, gold painted buttons and sliders, and an expanded 76-key keybed whose white keys also glow in the dark. Only 100 were made, and they were priced at US $3995.

The Yamaha TX802 was the rack-mounted equivalent of the DX7 II models, sharing their improved 15-bit outputs, patch memory, and additional voice features. This 2-unit high synthesiser expanded upon the DX7 II D by adding the ability to play up to 8 multi-timbral parts, each of which has its own individual output on the rear. Each of the 8 parts can be assigned to its own MIDI channel and to the stereo mixed outputs, 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.

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. The 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. Notable pop songs that use the preset are: "After All" by Al Jarreau, "Here and Now" by Luther Vandross, and Chicago's "Hard Habit to Break" among others.

Marimba emulation

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 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 immediate attack of the stock DX7 sound meant that the majority of users simply used the built-in marimba sound in the synth.

Bass/electric bass

Asian-European patch INT15 of the official ROM 1A and North American patch INT12 of the official ROM 3A were/was used widely throughout genres including hip hop, electro-hop, dance-pop, dance-rock and new wave in the 1980s, with examples of its usage including "Relax" by Frankie Goes to Hollywood, "Take On Me" by a-ha and "What Is Love" by Howard Jones. Unlike earlier synth bass sounds which were more quiet and featured a strong emphasis of a low-end sound, the DX-7 has a much brighter, almost stab-like sound to it.

Software emulation

Propellerhead has a Rack Extension emulating the DX7 in the Reason environment. Original DX7 patches can be converted to the PX7 format. is a multi-platform, multi format plug-in synth that is closely modelled on the Yamaha DX7. is a Disposable Soft Synth Interface plugin for Linux that emulates the DX7. It can load and edit DX7 patches directly. Native Instruments has developed a popular software synthesizer, the FM8 (2006) (previously the FM7 (2001–2006)), that includes the ability to 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. 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. Yamaha FS1R is an 8-op hardware synthesizer that can load DX7II patches (VCED and ACED bulk dumps) and accepts realtime DX7 sysex parameter commands.