Roland D-50

The Roland D-50 is a polyphonic 61-key synthesizer produced by Roland and released in 1987. Its features include Linear Arithmetic synthesis, on-board effects, a joystick for data manipulation, and an analogue synthesis-styled layout design. The external Roland PG-1000 (1987-1990) programmer could also be attached to the D-50 for more complex manipulation of its sounds. It was also produced in a rack-mount variant design, the D-550 (1987-1990), with almost 450 user-adjustable parameters.

The D-50's capabilities could be modified through the addition of third-party products by Musitronics, most notably the M-EX which made the D-50 multitimbral (the D-50 was bi-timbral), as well as a chip that improved the D-50's response to incoming MIDI commands and a system for burning custom PCM cards with user samples for playback in the D-50.

History
The D-50 was the first affordable synthesizer to combine sample playback with digital synthesis, a process that Roland called Linear Arithmetic synthesis. The engineers at Roland determined that the most difficult component of an instrument's sound to simulate realistically is the attack. To better emulate realistic sounds, the D-50 included almost 100 attack samples in ROM. The synthesizer played back an attack sample which was dove-tailed with more conventional subtractive synthesis to create the sustain of the sound. This dual-use method was required in 1987 since RAM was so expensive. Roland did, however, incorporate a number of "texture" samples that could be mixed into the synthesized sustain-part of a patch. These sustain samples gave many D-50 patches a lush and airy quality, particularly with its heavy use of choir, wind and string samples. The D-50 is probably the first virtual analog synthesizer. The D50 also was an early digital synthesizer to integrate onboard digital effects: it took the possibilities found in the 1985 Korg DW8000 digital delay section a step further by including better stereo imaging and an equalizer, to see Korg include more digital effects next year in their M1.

The Roland D-50 was awarded a TEC Award for outstanding technical achievement in musical technology in 1988.

Technology
Although the D-50 was among the first non-sampling machines to be able to produce sounds with sample-based characteristics, it was not long before many synthesizers on the market began using similar methods to create sounds. Roland later released a series of lower-priced keyboards and modules that allowed musicians who couldn't afford the relatively expensive flagship D-50 to have some of these sounds (Roland D-10 (1988), D-110 (rack version of D-10) (1988) D-20 (1988), D-5 (1989), MT-32). Though these lower priced D-series synthesizers did not contain the full "LA" synth engine, each was 8 part multi-timbral, and Roland doubled the number of onboard PCM samples. Roland also produced the 76-key, 6-octave "Super-LA" D-70 (1989-1990). With the D-70 Roland removed the digital synthesis section, which was replaced with full-length, more realistic and natural sounding samples, including an acoustic piano, which the D-50 lacked. The D-70 also had an expanded filter and effects section and was 5 part multi-timbral. Even with its improvements, however, the D-70 was unable to catch up with the dominant workstation of the time—the Korg M1—and failed to become the next Roland flagship synthesizer.

The D-50 produces a hybrid "analog/digital" sound: one can use traditional fat analog waveforms like saw and square (digitally created on the fly unlike competing synths of the time that used PCM samples of waveforms, ala Korg DW-8000) together with PCM samples of actual acoustic instrument attack transients and famous analog synths of the past, filtered through full analog-style processing (LFOs, TVFs, TVAs, ring modulator, effects, etc.). This breakthrough led to the creation of totally new sounds never done before on either pure analog synths or samplers.

Each D-50 sound ("patch") was made up of 2 "tones" (Upper and Lower) and each tone was made up of 2 "partials". Each partial could be either a "synth waveform" (pulse or sawtooth waveform) and a TVF (time-variant filter, the digital equivalent of a VCF) or a digital PCM waveform (sampled attack transient or looped sustain waveform). The partials could be arranged following 1 of 7 possible "structures" (algorithms), with a combination of either a PCM waveform or synthesized waveform, with an option to ring-modulate the two partials together. The synthesized waveforms could be pulse-width modulated and passed through a digital 4-stage Low-Pass filter, allowing for subtractive synthesis. The lower and upper part could be split or played in dual on the keyboard. The dual configuration allows an 8-voice polyphony bi-timbrality while only one partial plays, which allows for 32 voices.

Not only was the synthesis method new; the D-50 was arguably the first commercial synthesizer to include digital effects such as chorus and reverb, adding to the characteristically bright, rich, lively and sometimes realistic sound, featured on countless records of the period. Each of those effects had 10+ variations with editable parameters usually found in dedicated rack effects processors rather than keyboard synths. It was also on the forefront of the change of the look of a typical keyboard player on stage: instead of being surrounded with multiple instruments, with more versatile instruments and the continued adoption of the MIDI standard, they were starting to appear with only one or two keyboards, typically a D-50 with either Yamaha DX7 or Korg M1.

The D-50 was fully MIDI-compatible, though it transmits on only one channel. The keyboard was velocity- and after-touch-sensitive, and the keys were slightly "weighted" with metal for a higher-quality feel. It included 64 patches on-board, and 64 more patches were available on the expansion RAM card that was included. It uses a CR2032 lithium battery for memory backup.

For its sound and build quality, and the unique synthesis method it featured, the D-50 has remained popular to this day. Its synthesis engine, in more or less updated forms, was used in Roland's JV and XP series synths, among others. Furthermore, in 2004, Roland released a VC-1 expansion card for V-Synth and VariOS synthesizers. It contained a modeled and updated D-50 synthesis engine and the original operating system, including factory- and all Roland "expansion cards" patches. Since newer DAC chips sounded different (cleaner), it included the option to simulate the D-50's "rougher" output.

The D-550 is a rack-mount version of D-50, with fewer front panel controls, no joystick and sliders. It employs the same sound circuitry (the main circuit board is exactly the same in both, labeled "D-50/D-550")

Legacy
The D-50 was introduced in 1987 as the popularity of the Yamaha DX7 was declining, resulting in the D-50 being the most popular synthesizer on the market until the introduction of the Korg M1 the following year. The D-50's synthesizer-on-top-of-samples-and-through-effects innovation was an influence on the M1, which went on to become Korgs's top selling keyboard, until the release of the Korg Triton. In fact, this scheme was a common method of digital keyboard sound creation for more than a decade, until ROM and Flash RAM were finally inexpensive enough to store entire samples or multisamples.

In the case of the D-50, for sound synthesis, the use of PCM samples can be bypassed completely when using Synth Partials only as the basis for sound creation. This effectively gives 4 DCO subtractive synthesis (resonant filters), which can produce some very analog like sounds that later synths could not due to their sole use of PCM samples, or 'more digital' sounding synthesis methods (such as FM or PM) as the basis for their sound creation. This digital subtractive synthesis method of sound production gave a similar, but colder and more clinical, sound when compared to the analog technology employed by previous Roland synthesizers, e.g. the previous flagship JX-10.

The presets of the D-50, authored by Eric Persing and Adrian Scott, were well received by the artists' community, and most of them can be heard on numerous commercial albums of the late 1980s. The D-50's factory presets have enjoyed a long legacy, as patches like "Digital Native Dance", "Staccato Heaven", "Fantasia", "Glass Voices", and "Living Calliope" are so common that they border on cliche. Some other D-50 presets live on in every machine that conforms to the General MIDI specification, including "Fantasia" (alternatively called "New Age Pad"), "Soundtrack", "Atmosphere", and "Nylon Atmosphere".

The Roland V-Synth and V-Synth XT can load a card which emulates the D-50. In this mode, they copy the D-50 almost perfectly, although they lose the more sophisticated V-Synth capabilities.

On September 8, 2017, Roland announced the Roland D-05, a miniaturized version of the D-50, as part of their Boutique series. The instrument includes the original presets of the D-50, plus all of the ROM expansions Roland created for it. The instrument was released in October 2017.

Also in 2017, Roland released a VST plugin version of the D-50. via their Roland Cloud website.