Black Corporation Deckard's Dream

While emulations of other classic analogue synths abound, there's only ever been one way to get your hands on a CS80 — until now.

Over the past few years we've been inundated with wonderful recreations of venerable analogue synthesizers: the Minimoog, the ARP Odyssey, the Korg MS20, the Oberheim SEM and, with an extra voice, the Prophet 5. Nonetheless, fans of the Yamaha CS series (whether monophonic or polyphonic) have been poorly served up to this point. In fact, they haven't been served at all. Until now.

A remarkably sophisticated synthesizer for its era, the CS80 was based upon two independent eight-voice, VCO/VCF/VCA synthesizers represented by a single row of controls that Yamaha called 'Channels' or, individually, Synth I and Synth II, and which Black Corporation calls Layer I and Layer II. A third row of faders and a panel alongside the keyboard then controlled tuning, modulation, and performance parameters. A quick visual inspection shows that, with a handful of significant omissions, Deckard's Dream recreates this architecture with remarkable accuracy, so seasoned CS80 aficionados should feel at home with it.

Side By Side

I was keen to compare the two instruments, so I placed Deckard's Dream alongside my CS80 and started with an evaluation of their oscillators. On Deckard's Dream these are based upon the recently recreated CEM3340 oscillators from On Chip. As on the original synth, they produce sawtooth, pulse and sine waves, the first two of which pass through the filter section while the third is injected directly into the first of the VCAs that follow the filter section.

I began by comparing their sawtooth waves and found them to be all but identical. The square waves on my CS80 were a touch brighter than those of Deckard's Dream but this was a consequence of 42 years of drift; the two instruments sounded alike after I tweaked the pulse width on the CS80. Turning to the pulse-width modulation (PWM) I found that the slowest sweep on my CS80 was slower than the slowest setting on Deckard's Dream, and the fastest setting on Deckard's Dream was faster than the fastest on the CS80. However, when I turned to the Settings menus in Deckard's Dream I found all manner of 'per-patch' parameters, some of which allowed me to adjust the time constants of various functions. In this case, I was able to reduce the minimum PWM rate from around 0.7Hz to 0.1Hz, and increase the maximum from around 70Hz to 100Hz. Nonetheless, the maximum PWM depth was still greater on the CS80, and there was no way to make Deckard's Dream equal this. Perhaps by way of recompense, you can choose between two global PWM modes: Separate, in which the PWM rates of Layer I and Layer II are independent of one another, and Sync, in which they're not.

Turning to the sine wave, I found that I could obtain a higher maximum level for this on the CS80, especially at low frequencies. But perhaps the greatest difference between the raw sound sources of the two instruments lies in their noise generators. On the CS80, the noise has a high maximum amplitude and significant low-frequency content while, on Deckard's Dream, it's far whiter and has much lower amplitude. This means that patches based upon noise or which mix cyclic waveforms with noise may not sound the same on the two instruments.

Filters, Envelopes & Amplifiers

The CS80 offers a pair of filters for each voice, a 12dB/oct resonant (but not self‑oscillating) high-pass filter and a 12dB/oct resonant (but not self-oscillating) low-pass filter. Comparing Deckard's Dream to the CS80, I have to admit to being impressed with its LPFs; not only do they open and close to the same degree, they do so with the same timbral effect at all resonance levels. The sound of the high-pass filters is less similar to the original's, with the CS80's having a more pronounced effect on the sound, but I'm not complaining. When you see what Scott Rider had to do to reverse-engineer and recreate these circuits (see http://synthtech.com/motm/480/) you'll stand in awe of his expertise.

The front panel should be familiar enough to anyone who's played a CS80, although you'll have to look to the menus or forthcoming expander module for some of the missing functions.

The cutoff frequencies of both filters in a given Layer in Deckard's Dream are affected by a digitally generated four-stage contour. This is described in different places in the manual as an ADR and as an ADSR envelope generator, but in both cases that's wrong. As on the CS80, it's described by five controls: the Initial Level (IL), the Attack Level (AL), the Attack Time (A), the Decay Time (D), and the Release Time (R). You may wonder how or where the Sustain is defined, but it's not. The sustain level is always zero, and its relationship with the start/end and peak values is determined by the IL and AL settings. The minimum attack time on a CS80 is short — a slightly squelchy click — but, at just a second or thereabouts, its maximum is remarkable short. At around 7s and 12s respectively, the decay and release times are also short when compared with other analogue polysynths. The default settings on Deckard's Dream are similar to these times, but you can adjust the maximum lengths of each of the phases on a per-patch basis, increasing the maximum attack to 100 seconds and each of the decay and release to maxima of 150 seconds, which is an excellent improvement. Furthermore, you can invert the action of the high-pass filter contour on Deckard's Dream so that both filters open simultaneously if desired rather than one opening while the other closes. Unfortunately, this is a global setting, so you can't create a patch library in which some sounds have the filters responding as on the original and some in which they respond with opposite polarities.

Two further controls in the Layer affect the filter, and you'll find these at the far right-hand end of the panel. They are labelled Initial Brilliance and After Brilliance, and they determine how much effect velocity and aftertouch have on the filter cutoff frequency. This is where the famous polyphonic aftertouch of the CS80 is applied.

The signal generated within each voice now reaches a pair of VCAs in series. There are two inputs to the first: the output from the filter and the sine wave that bypasses the filter. Its gain is then controlled by a digitally generated ADSR contour with similar time constants to the filters', and, again, you can increase the maxima on a per-patch basis. The second VCA has three control inputs. The first is a simple level control that sets the loudness of the Channel, while the other two determine how much effect velocity and aftertouch have on the gain of the VCA.

By this point, I was already impressed with Deckard's Dream, and had uncovered only one problem, albeit an inconsequential one: it suffers from bleed from Layer II into Layer I. This isn't a problem in use because you either want Layer II in the sound, or you can silence it by switching off its oscillators, but it's worth noting nonetheless.

Modulation & Control

The third row starts with the coarse and fine tuning controls. On my CS80, the former of these has a range of +7 and -4 semitones, while on Deckard's Dream the range is +6 and -7 semitones. On both instruments, the fine tuning is somewhat less than a semitone. Alongside these, there's a detune control that allows you to sharpen or flatten Synth II by up to a semitone or so with respect to Synth I to create the usual fatter sounds and effects.

The next group of faders found on the CS80 is missing from Deckard's Dream and these controlled a facility that did much to cement the instrument's place in the pantheon of the world's most desirable synthesizers. It's the Ring Modulator and, if you're a fan of music recorded using the CS80, you'll bemoan its absence. Happily, all is not lost... Black Corporation make an expander for Deckard's Dream that contains this.

Now we come to the CS80's LFO section. Although this is digitally implemented on Deckard's Dream, the controls are again mimicked, although they now sit to the right of the footage selectors rather than to the left. The same six sources are available (sine, sawtooth, ramp, square, noise and external) with the same control over rate and the amount directed to the oscillators, filters and amplifiers. The depths available on both instruments are similar so, overall, very similar results can be obtained. However, Deckard's Dream has an Extended 'per-patch' LFO Depth parameter in its menus, so you can create a wider range of modulation effects should you choose to do so. Likewise, while the frequency range of the CS80's LFO is wider than the default settings of Deckard's Dream, you can extend the range on a per-patch basis from the default of around 0.7Hz‑25Hz up to 0.1Hz‑45Hz, which means that Deckard's Dream can do everything that the original can do, and more. Furthermore, there are two LFO modes: Poly and Mono. When Poly is selected, Deckard's Dream generates independent LFOs for each voice. In Mono mode, a single LFO is used for all voices as it is on the CS80. The Mono mode is not free running but, since it's initiated by the first note pressed in a chord, the effect is generally much the same. (But not always!) Unfortunately, the LFO mode is Global, which is a shame.

Notwithstanding their differing positions, the footage controls on the two instruments are the same, with one strange anomaly: with a standard 61-note MIDI keyboard controlling Deckard's Dream and set to the standard MIDI note range for such keyboards, you have to set the footage an octave lower on Deckard's Dream to obtain the same pitch.

Jumping over the CS80's preset tone selectors, we now come to the Mix I/II control that allows you to blend the two Channels. Next to this lie the global controls for brilliance and resonance. These shift the pass-band of the HP/LP combination, and increase or decrease the resonance of both filters in the voice in a single operation.

The next control determines how velocity affects the amount of an upward pitch sweep at the start of each note to create an effect that, in the 1970s, was sometimes called Slalom. The next three determine how pressure affects the LFO rate and the amount applied to the oscillators' pitch and the filters' cutoff frequencies. (The manual says 'velocity' rather than 'pressure' but that's another error.) On the CS80, the results can be wonderfully musical but the amount of pressure that you need to apply using a typical MIDI controller keyboard to obtain the same effect on Deckard's Dream can be rather greater, and there appears to be no way to adjust the curve or the sensitivity. In general, you can adjust such things on the controller keyboard, but not always, so perhaps this is something that can be added in a firmware update.

The final set of tabs on the third row of the CS80 offers yet more control over the filters and amplifiers. In modern parlance, these would be called keyboard tracking controls but, instead of determining a single slope across the whole note range, you are offered two controls: one that affects the upper two octaves of the keyboard, and one that affects the lower two. (The middle octave is largely unaffected.) The same controls are offered on Deckard's Dream, and these work in the same way but with reduced effect until you tweak the Tracking Width parameter in the Settings menu.

The CS80 has a fourth panel located to the left of its keyboard. This comprises controls for its chorus and tremolo effects, portamento/glissando controls, a sophisticated sustain section that allows for both individual note sustains (Sustain I) or a global 'return to zero' when new notes are played (Sustain II), and for pedal control over sustain, portamento/glissando, VCA gain, and combined VCA gain and VCF cutoff frequencies. These facilities were remarkable in 1977, and still do much to make the CS80 the exceptional instrument that it is. Deckard's Dream's control panel lacks all of these except for a portamento/glissando selector and rate slider. However, the Settings menus allow you to choose between Sustain I and Sustain II, your choice of which can be stored on a per-patch basis. Other functions can be controlled via MIDI. Elsewhere, you'll find the chorus and vibrato effects alongside the ring modulator in the Expander. Given the great care taken to imitate the CS80, I wonder why Black Corporation lessened the illusion with these omissions?

Other Facilities

One of the most important features of the CS80 was its polyphonic aftertouch, which meant that, while holding a chord, you could lean on any given note and obtain the programmed effect without affecting any other notes sounding at the same time. If this is important to you, Deckard's Dream offers it via MIDI and MPE (MIDI Polyphonic Expression), the latter of which is the protocol generated by the Haken Continuum and the ROLI Seaboard. In addition, it accepts the MIDI CC74 message generated when you move your fingers backward and forward on the keys of a Continuum or Seaboard, allowing you to map this to a single destination chosen from the LFO rate, the LFO amount, the overall brilliance, and the cutoff frequencies of each of the four filters in a patch. Similarly, you can determine which parameter is controlled by modulation wheel messages, and with what polarity. These include the LFO depth, the brilliance, the portamento rate (described in the manual as Portamento Level) the PWM rate, the detune amount, or the VCO footages.

You can tailor Deckard's Dream further by selecting the pitch-bend range and by balancing the levels of individual patches within the range ±6dB, which is vital for live work. You can even create a micro-tuned scale, but this is a global setting and, while it might sound great when used with your Indonesian metallophone patches, it may not work so well for your western sounds. At any time, you can reset all of the parameters found in the menus to their defaults, but be very careful with this. If you've used them when creating specific patches, you'll change your sounds — perhaps fundamentally — and it could be difficult to track down the culprit.

Finally, it's worth noting that Deckard's Dream has an advanced MIDI specification with 79 MIDI CCs controlling just about every voicing parameter, which means that full automation should also be possible.

The Sound

Deckard's Dream has 384 memory locations, 128 of which contain preset factory sounds, and 256 of which are user memories. Unfortunately, there are no shortcuts for selecting sounds. You have to select the bank you want to access and then tap the Up or Down buttons until you reach the wanted memory. Sure, you can select sounds using MIDI Program Change messages but this won't always be convenient, and doing so from the front panel can be long-winded and frustrating, especially since you have to press Down to increase the patch number and Up to decrease it. This may sound like a small point, but it's so counter-intuitive that it will catch you out every time.

That still doesn't answer the question... does it sound like a CS80? Although it uses modern technology rather than the original Yamaha modules (which raise the concept of unobtanium to a whole new level) it gets very close, more than close enough to substitute for the original as long as you don't push the high-pass filter to its extremes or require the ring modulator or effects. As for the sounds themselves, I think that I'm in love. There's something special about the CS80, which can sometimes sound a bit weak and nasal in isolation, but which can exhibit immense depth and work perfectly in a mix, and so it is with Deckard's Dream. But don't take my word for it; there are some great examples on the Deckard's Dream website — particularly those by Paul Schilling, who has explored the sounds used by Vangelis on Spiral, China, Chariots Of Fire and Blade Runner, and which were instrumental (no pun intended) in cementing the CS80's fabulous reputation. There are also some remarkable recreations of sounds that I know were recorded on Prophets, Oberheims, various Moogs and even a GX1, proving that Deckard's Dream is more than just a CS80 clone. Indeed, stepping far beyond the capabilities of the CS80, it offers three voice modes that can be programmed on a per-patch basis: eight-voice polyphonic, monophonic, and eight-voice unison. Used together with per-patch detuning, the last of these allows you to create some huge sounds. There are also two global sub-modes: one voice per note, and two voices per note. The latter of these reduces polyphony to four notes but, again, the results can be fabulous. Furthermore, a Chain parameter will eventually allow you to chain together two Deckard's Dreams. The firmware is still under development but, once implemented, will allow you to create the equivalent of a 16-voice CS80, or a four‑Channel eight-voice CS80. Wow!

Should you want to back up your sounds, you can do so by connecting Deckard's Dream to a computer via USB and firing it up in USB Drive mode, at which point it will appear as an external drive. You can then drag-and drop memory banks from and to the synth, but there doesn't appear to be any way to back up individual sounds, which is an annoying omission.

However, my main criticism of Deckard's Dream concerns the digital part of its editing system. The screen is incredibly small and the navigation system is a throwback to the worst of parameter‑access programming. With five tiny buttons (Up, Down, Enter, Cancel and Shift), messages that send you scurrying for a magnifying glass, and a bunch of arcane button presses, this is far from the clear screens, informative graphics and soft keys that we've come to expect from elsewhere, which is why the software editor (see box) will be so important. The on-board system won't stop you achieving the results you want, but it may drive you mad while you do so.

Conclusions

The idea of a modern CS80 will excite many players and Deckard's Dream fulfils this role admirably. With additional parameters, new voicing modes, MIDI automation and more, it also goes far beyond the original without ever sacrificing its underlying character. I asked Black Corporation whether a keyboard version might be in the works but they responded that it's not; they won't even consider this until a suitable poly‑aftertouch‑capable keybed becomes available. But for now, weighing nearly 100kg less than its inspiration and occupying just 4U, Deckard's Dream will fit into every studio and bedroom in exactly the way that an original CS80 doesn't.