The company Moog is probably best known for its famous MiniMoog, its huge modulars and, to a lesser degree, the MultiMoog, MemoryMoog, etc.. All of these used a collection of oscillators which were mixed and sent through a filter and then out to the output amplifier. They all required a certain knowledge of synthesis to get anything out of them.

However, Moog also dabbled in other, simpler products aimed at a wider audience. One such product was the Moog Opus.

The Opus was a very 'novice-friendly' polyphonic synth released in 1980 that offered three sounds simultaneously thus you could layer strings, organ and brass. The polyphony was, like the ARP String Ensemble and other string synths, derived from 'divide-down' electronic organ technology and so was totally polyphonic. However, its limitation was that there was just one filter and envelope to service all voices and so it was necessary to modify your playing technique to articulate sounds correctly. Whilst this may seem like a big limitation, it was common for this kind of synth at the time

The string section was made up of a sawtooth wave that passed through quite a comprehensive multi-mode (but static) filter for tonal modification and an envelope shaper. The 'ensemble' sound was created using a multi-stage chorus unit.

The organ section featured variable drawbars that allowed a great range of organ sounds to be created. This could also also be passed through the chorus unit to add a kind of 'leslie' effect.

Finally, the brass section (again, using the same basic sawtooth wave as the string sound) had a filter section and simple envelope generator that you could use to create brass and simple polysynth sounds.

All three sections could be mixed and (unusually for the time) panned allowing you to stack up a huge stereo sound. Each section was also colour coded (red for strings, green for the organ and yellow for brass) which made it very easy to use even without much (or any) experience.

The Opus also featured a dynamic resonant lowpass filter with its own simple AR envelope generator and the strings and/or the brass could be routed to this for greater tonal variation and the creation of rudimentary synth sounds.

Like other Moog products of the time, however, it was not a huge success. The Prophet 5 and Oberheim polysynths were dominant, Moog came too late to the market with the Opus and it offered nothing new - remember that Elka, Crumar, ARP and others had had similar products like this out for several years by the time the Opus was released. However, it was a fine sounding keyboard and the string sound was particularly lush.

This donation comes from Akai Z4 user, Paul Marshall, who has meticulously sampled the string sound from his own Opus at every major third across its 4-octave keyboard range. He has sampled the Opus's two footages (8' and 4') separately and whilst Paul could have taken the easy route and simply layered these samples to create a combination of the two footages, instead, he has painstakingly sampled the Opus's original 8' and 4' combination for a truly authentic sound. Each sample is around five seconds long with long, seamless loops which have been carefully hand-converted to Kompakt for Nostalgia.