Sound Of Music

Model	Roland D-550
Type	Synthesizer
Synthesis	Digital LA
Manufactured	1987-1989
Quantity
Polyphony	16 Voices
Oscillators	32 partials (sampled attacks or digitalized waveforms)
Filters	TVF (Time Variant Filter)
Memory	64 patches and additional 64 on ROM/EPROM-card (optional)
Keyboard	-
Sound	Big and warm
Good for	Synth sounds, bells, analog sounding pads and synth brass
Less good for	Acoustic instrument
Miscellaneous	Not multitimbral as standard, but it was possible to build in a third part card for this (MEX-cards)

BACKGROUND

1983 -1987 was dominated by one synthesizer: the Yamaha DX7. 1987 was the Roland D-50 released and the rack variant D-550. The next year Roland started to release different cut down versions of the popular D-50. The most exclusive of them was the rack model D-110 that became popular in the late 80s. One unique thing with D50/D550 when it came was that it had an onboard digital reverb and fx processor. Another thing was that it replaced all other synthesizers for keyboard players because the large sound.

DESCRIPION

Roland D-550 is a 16-voice, Bi-timbral (can use two sounds), 2 HU rack mounted synthesizer module with LA-synthesis.

D-550 is the rack model of D-50
D-70 is as a 76 keys U-20 sample player (inside early-rev D-70 reveals the emblem U-50 inscribed onto most of the circuit boards)
D-550/50 had later four cut down models (with thinner sound): D-5, D-10, D-110 and D-20. There is also the low budget module MT-32

The sound architecture in Roland's LA-synthesizers (Roland D-series) is built like this:

Partial - the smallest piece. In D-550 one or two partials creates a tone
Tone. On the same level is a Timbre, that is an edited Tone. In D-550 two timbres (lower and upper) creates a patch
Patch, that is the sound that you play, with all adjustments and FX

The sounds can be spread on the keyboard in these three ways:

Single - One sound on the whole keyboard
Split - Two sounds with a split point
Dual - Two sounds layered

As an option there was a card by Musitronics that made the D-550/D-50 multitimbral (MEX-card) and expanded the internal 64 patches to 192 multimode patches, 10 new displays and 42 new parameters.

The D-550's parameters can be accessed from the knobs on the panel. But its easier with the programmer PG-1000 (optional) with knobs and slides for all the functions on the D-550.

PG-1000
PG-1000

D-550/D-50 arrived with 64 presets that soon became classic, for instance Fantasia and Heaven. There is a slot for card with additional 64 sounds on the front panel. The D-550/50 is not multitimbral, it can just play two sounds at the same time. And it has no drum sounds. But the sounds are huge. It has internal FX-processor with reverb, delay, chorus, EQ and more.

When D-550/D-50 released it hit knockout on the whole synth business. The keyboard players had earlier huge machine parks in live situations. Now it was enough with just one or two synths. It had large and useful sounds. A typical keyboard setup at the end of the 80s was like this:

1 D-550/D-50 (+ one keyboard)

or

1 D-550/D-50 and 1 DX7

The rear of D-550: