My first couple of chords on a D50 back in 1987 convinced me that I was witnessing something special. Those lush strings, the mind-blowing (and, subsequently, mind-numbing through overuse) 'Digital Native Dance', and the swirls and swooshes of countless choir, string, and blown-bottle pads came as a revelation to ears jaded by years of analogue bleeps and FM clangs.
Roland proudly labelled their new technology 'Linear Arithmetic' synthesis -- or LA for short. Despite the swish name, the internal architecture of the D50 is not particularly exciting by today's standards, and does little to convey the reason for the machine's lasting appeal. LA synthesis was essentially the first of the Sample+Synthesis (S+S) instruments, which have dominated music technology for the last 10 years -- only now being overtaken by the new wave of physical modelling synthesizers. At a time when we were all fed up of not being able to program our FM synthesisers, it came as something of a pleasant surprise to find that Roland had essentially stuck to the analogue terminology with which most synthesists were familiar. OK, the VCA and VCF of old had become the TVA and TVF in the D50, but they worked in pretty much the same way.
A D50 'Patch' is the standard unit of currency, consisting of a pair of 'Tones', designated Upper and Lower. Within each Tone are a pair of 'Partials', each of which can be thought of as a single-oscillator synth. A number of 'Structures' specify whether each partial is to produce a standard synth waveform (sawtooth or square, with adjustable pulse width), or make use of one of the 100 PCM samples. With memory costs at a premium at the time of the D50's release, Roland had to work hard to make the most of the available space. Whereas the short attack samples, such as trumpet spits and flute chiffs, are generally good, some of the looped sounds are questionable. Of the 100 samples, 47 are attack portions, 29 are static looped waveforms, and 24 are actually loops that scan across several of the D50's shorter ROM samples to create some strange rhythmic effects -- 'Digital Native Dance' being a prime example.
But what the D50 lacked in refined sample material it certainly made up for in the synthesis department. PCM partials have a relatively easy life of it, being subjected to LFO and envelope pitch modulation before being routed through the Time Variant Amplifier (TVA). Synthesizer waveforms enjoy the added pleasure of being mangled by the Time Variant Filter (TVF). This resonant filter is one aspect of the D50 that holds much of the machine's lasting appeal, I'm sure. It doesn't have the slurpy resonance of an analogue synth, admittedly, but it has plenty of warmth and character to keep you coming back for more. Three assignable LFOs are available, and pitch, filter and amp each have their own dedicated multi-stage envelope generators, making a very flexible set of sound-producing tools. The range of modulation options is quite sophisticated, with the ability to use positive or negative phases of the LFOs, and to adjust the key-follow curve based on a bias level and keyboard-split point. Several of the Structures include a ring modulator, which is capable of some excellent effects when patched between a pair of PCM samples.
Tone parameters include the three LFO waveforms' delays and speeds, pitch-envelope and chorus settings, and there's also a very useful high/low EQ section with variable frequency and gain. The high EQ even has adjustable Q (frequency bandwidth). The chorus is typically Roland and typically good, with eight different types of chorus including flangers, tremolo and Roland's hugely desirable 'Dimension' chorus effect.
Two Tones do a Patch make, and here it is that reverb or delay is added, key modes are set, and split points are defined. Usefully, each Patch can be set to transmit on a different MIDI channel and to send a program number between 1 and 100, which makes it a good master keyboard for live situations. Another aspect worthy of note is the 'Chase' play option. Chase can essentially be thought of as similar to the MIDI delay processors found in many software sequencers, but the D50 switches between the Upper and Lower Tones between repeats. This is a very inspiring feature, which has helped my creativity along on more than one occasion. If only Roland had added an arpeggiator into the bargain! The D50 can be used as a bi-timbral instrument if you specify a second channel to which the Upper Tone can be assigned.
The D50's keyboard is quite smooth and pleasant to play, making it a good master keyboard, provided that a weighted action is not a priority. Much less successful is the bender/modulation lever, which is far from ideal. For pitch-bending, I am more than happy with Roland's device, but as a modulation source it has too short a travel to be much more than an on/off switch! The onboard joystick can be used in editing and also pressed into service as a performance device for fading between the Upper and Lower Tones and also between the Partials of either of the Tones. This is a neat feature, but don't expect to go recording the results into your sequencer, because the joystick doesn't transmit any MIDI data. External storage is possible via MIDI System Exclusive, although a card slot is available.
The times, they have been a-changing, and the D50 has much less impact on ears well used to the complexity of sound offered by later instruments. Those lush strings now have some dubious loop points and there's a whole lot of nasty aliasing noise going on in the higher octaves; the rhythmic loops that sounded so inspiring are now annoyingly dated, and there's no way of changing them. But there are still sounds of which only the D50 seems capable. The ethereal 'Glass Voices' is still the mainstay of much new age and electronic music, and the gritty Hammond organ emulations are among the best of their kind.
If the D50 has an Achilles heel it is that although many of its sounds are extremely lush and sexy when heard in isolation, they tend to turn into an unpleasant mush when placed in a mix. A lot of the blame for this must be placed at the door of the effects section, which is often overused (especially in the factory presets) to make up for the short loops and gritty samples. With a few judicious edits, things can get a whole lot better -- I've known many players who turn off the D50's internal reverbs altogether. Although the results may be thinner and less impressive on their own, the same sound in a mix is much more comfortable. Don't expect any realistic instrument emulations, and forget the piano patches (unless you're looking for a piano that sounds as if it was made for the Early Learning Centre!). But marvel at the powerful strings, the breathy, tinkly pads and the cheesy organs -- and if you ever get hold of the 'Star Trek Voices' patch then you'll be one step closer to becoming a film-soundtrack writer, perhaps...
Korg's M1 was arguably the synth most responsible for deposing the D50. Capable of a similar style of sounds, aided and abetted by a considerably more powerful effects processor, and -- most importantly -- multitimbral, the M1 stole the D50's glory and went on to become a milestone itself. Many LA synthesis spin-offs were to see the light of day following the D50's release, the best known of which is likely to be the multitimbral D110. Roland were also later to release the D70, which was based on the same LA synthesis technology pioneered by the D50. But whereas the D50 was fairly easy to get to grips with, the D70 proved to be more difficult to master, and somehow never had the sound texture of the earlier machine.
So is a D50 worth tracking down? Well, as always, that is essentially down to the individual. If you're after the aggressive bite of FM sounds, then the D50 is not going to satisfy. Similarly, if you want the squelch and immediacy of an analogue synth, then the D50 will probably disappoint. But I would defy anyone not to be impressed by the power and depth of many of the D50's pad-type sounds -- they swirl and swoosh in a most appealing manner, which few synths since have been able to emulate. It can't be denied that there is a definite late-'80s edge to the D50's sound, but that has much to do with the fact that the D50 was the late '80s sound!
The rackmounting D550 is a good option, given that the D50 itself doesn't lend itself particularly well to on-the-fly editing. The D550 has a slightly better MIDI specification, making life easier for librarian software to get Patches and reverb settings. Several operating-system upgrades were made available by third-party companies. The Musitronics M-EX is probably the best known, and gives the D50 multitimbrality among a host of other useful features. Early versions of the M-EX were reportedly troubled by some unpleasant bugs, so try to check things out thoroughly before buying a machine with any such options added. Aim to find a machine that still has the factory ROM card and at least one RAM card too, if possible, as this effectively doubles the number of Patches available. And watch out for broken D550 joysticks -- they stick out from the front panel and are particularly prone to damage.