Its features include digital sample-based subtractive synthesis, on-board effects, a joystick for data manipulation, and an analog synthesis-styled layout design.
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.
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-50 produces a hybrid analog/digital sound: one can use traditional square and saw waveforms together with PCM samples of actual acoustic instrument attack transient, modified by LFOs, TVFs, TVAs, ring modulator, effects, etc.
The synthesized waveforms could be pulse-width modulated and passed through a digital mathematical approximation of a low-pass filter, allowing for subtractive synthesis.
[4] Not only was the synthesis method new; the D-50 was arguably the first commercial synthesizer to include digital effects such as reverb, adding to the characteristically bright, rich, lively and sometimes realistic sound, featured on countless records of the period.
It contained a modeled and updated D-50 synthesis engine and the original operating system, including factory- and all Roland expansion cards patches.
It employs the same sound circuitry (the main circuit board is exactly the same in both, labeled D-50/D-550) 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) and expanded the patch memory, as well as a chip that improved the D-50's response to incoming MIDI commands.
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.
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, such as "Digital Native Dance", "Staccato Heaven", "Fantasia", "Pizzagogo", "Glass Voices", and "Living Calliope" .