Yamaha DX7

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Yamaha DX7

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W × H × D (mm)	101.8 × 10.2 × 32.9
Weight	14.2kg
Type	6 operator FM Synthesizer
Keyboard	61 Keys with initial and aftertouch sensitivity
Manufacturer	Yamaha
Release date	1983
Parts	1 (Monotimbral)
Max polyphony	16
Normal presets	32
Expansion	DX7 Voice Cartridge

The Yamaha DX7 is a 61-key, 6-operator FM synthesizer keyboard created by Yamaha in 1983. It's one of the most famous synthesizers ever made. It was incredibly successful and especially popular in the 1980's. Many of its tones appearing in popular music and productions of the time. Many of its sounds (Such as the unique glassy rhodes tone, its very distinctively harsh digital bass sounds, and many more) to this day are still production staples, having been sampled in countless sample-based synthesizers and most notably in the General MIDI spec, as the Electric Piano 2 program.

It employs 6-operator FM synthesis as its main source of sound generation, with 32 algorithms. The DX7 comes with 2 sound cartridges, with the first 32 preset voices of the first one loaded in internal memory.

FM Synthesis

Contrary to a lot of marketing, the DX7 actually implements phase modulation synthesis; rather than modulating the frequency of each oscillator, it modulates its phase instead. For DX7's implementation, where only sine wave-based operators can be used, this is perfectly equivalent to frequency modulation, however later Yamaha FM synths that use non-sine wave based oscillators (such as the TX81Z) would have a slightly different sound compared to FM implementations.

Regardless of such, FM synthesis provides a very different paradigm compared to more traditional subtractive synthesis - rather than having a sound that you can use a filter to remove parts of the sound, you are provided with many different "operators", which can rapidly sweep the pitch (or phase) at audible rates to create harmonically rich sounds. When tuned precisely to ratios (such as 2x, 3x and so on), this can create very sharp and bright sounds, uncharacteristic of typical subtractive synthesis, especially of its era which employed much simpler sawtooth or pulse waveforms. The user also had the choice to run these operators at a "fixed" frequency, which did not scale with the frequency played, to create harsher sounds.

32 algorithms are provided to the user, which link up the operators in different ways. The operators that actually output audio are referred to as carriers, while an operator that links to one or more operators are referred to as modulators. It is worth noting that modulators can feed into other modulators, however the relationship of this is dependant on the algorithm chosen. One operator has access to a "feedback" parameter, which lets it modulate itself, regardless of whether it is a carrier or modulator.

Emulations and recreations

As the DX7 is quite a popular synthesizer, and because the sound production method isn't strictly tied to including an entire bank of ROM waveforms, there are quite a lot of emulations and recreations available, either as free open-source software or as paid software, or even hardware.

Dexed

By far the most popular recreation. It is available as a free VST and standalone program, and has the ability to interface with a real DX7, acting as a librarian. It is also fully open-source and has an interface that allows for full patch editing. It is regarded as difficult to use for patch creation by some.

Chipsynth OPS7

This is a modern recreation that tries to accurately recreate all the quirks of the DX7, from some of its software quirks to the compander-based DAC. It can also act as a librarian, but also implements a number of features not available on the DX7, such as a dual voice system reminiscent of the DX5 and DX1, or the later DX7ii, extra waveforms taken from the TX81Z, the YMF262, or even the AFM engine from the SY77. The interface is easier to use than Dexed's and offers a similar user interface to Chipsynth MD. It is available as a one-time paid purchase from Plogue's storefront.

Arturia DX7 V

This is another modern recreation. It implements SysEX support, but cannot act as a librarian. Many extra waveforms are implemented, as well as a wealth of new features, a modulation matrix, and a nice graphical interface. It also has a built-in velocity scaling feature, allowing the user to either use the full 0-127 velocity range, or limit it to 0-99 as per the original DX7 keybed. It can be acquired from Arturia's storefront but is quite expensive on its own.

Korg Volca FM & Volca FM 2

This is a compact hardware unit with a built-in sequencer, it has 3-voice polyphony, it can load DX7 SysEx files. The Volca FM 2 doubles this to 6-voice polyphony.

Oddities

• The DX7 was made very early on when the MIDI protocol was still new, so its implementation has quite a few oddities and quirks such as:
  • It transmits velocity only up to 100, though still can receive up to 127.
  • It can only transmit on Channel 1 (but can still receive on any channel).
  • Aftertouch was a CC parameter rather than a controller type of its own (this was since corrected in later firmware).

• The DX7 Manual has an error on page 1 that states the keyboard is expandable up to 128 preset voices when it can only interface with up to 96 when considering the 32 Voice Preset Internal memory and an external 64 Voice cartridge.

External Links

• DX7 Operating Manual + MIDI DATA Format
• DX7 Voice Library with Performance Notes