My Perfect Synthesizer

February 17, 2022 0 By GerenM

Over the years, I’ve given a lot of thought to my idea of the “perfect synthesizer.” Although some have come close, it has yet to come along.

Let’s lay out my criteria for a perfect synth:

  • 3 Digitally Controlled Analog Oscillators
    • Each oscillator has Sine, Triangle, Saw, Super-saw, Square, and Pulse waveshapes plus white/pink noise
    • Each oscillator has pulse width/wave shaping/wave distortion
    • Each oscillator has independent or syncable pitch envelop
      • depth control
      • cycling option
    • Oscillators can be cross-modulated and/or synced
    • Oscillators can be independently tuned
    • Minimum of 6 voices per oscillator
    • Stereo/binaural voice spreading
  • 3 Independent Digitally Controlled Analog Filters
    • Each filter offers multiple modes (LP, HP, BP, etc.)
    • Each filter offers 2 or 4 pole operation
    • Each filter has independent or syncable ADSR envelop
      • depth control
      • cycling option
    • Each filter can be fully independent or synced
    • Each filter offers variable key tracking
  • 3 Independent Digitally Controlled Analog Amplifiers
    • Each DCA has independent or syncable ADSR envelop
      • cycling option
    • Each DCA has independent master level control
  • 3 Independent Low Frequency Oscillators
    • Each LFO has Sine, Triangle, Saw, Square, Sample and Hold, and Random wave shapes
    • Each LFO can be free-running or key-triggered
    • Each LFO has at least basic amplitude envelop
    • Each LFO has master depth control
    • LFOs can be routed to oscillator pitch, filter cutoff, filter resonance, and amplitude with variable depth
    • LOFs have fade capability
  • Master Effects Section
    • Distortion/Fuzz/Overdrive
    • Modulation Chorus/Flange/Phaser/Pitch Shift
    • Delay/Echo with tempo sync to MIDI clock or internal sequencer/arpeggiator
  • Patches can be easily saved and retrieved
  • Selectable mono or poly mode
  • Portamento with separate “amount” and “on/off” controls
  • Front-panel transposition and octave controls
  • Internal arpeggiator
    • Syncable to MIDI clock or internal timebase
    • Up/Down/Up-Down (inclusive and exclusive)/Random/Ordered/User patterns
    • Swing
    • Chord and Scale modes
    • Tempo divisions from 1/4 to 1/32 plus triplets
    • Strum modes
    • Velocity-controlled arpeggiation range
  • Internal sequencer/phrase recorder independent of patches
    • Syncable to MIDI clock or internal timebase
    • Up to 64 steps per sequence
    • Parameter locking per step
    • Swing
    • Chord and Scale modes
    • Pattern chaining/song mode
  • Comprehensive I/O
    • Stereo output
    • Headphone output with separate level control
    • External stereo input routable to DCF(s), DCA(s), and effects
    • 5-pin MIDI In/Out/Thru
    • Class Compliant USB MIDI and Audio
    • Pedal inputs for Sustain/Damper and Expression
  • Minimum of 64 internal patches plus external USB patch storage
  • 49 or 61 full-size keys with velocity and polyphonic aftertouch
  • Pitch Bend and Modulation controls (wheels or joystick)
  • Knob/button/switch per function (minimal menu diving)
  • Full MIDI implementation
  • Mains, battery, or USB power
  • Computer (Windows/Mac/Linux) or app-based (iOS/Android) editor
    • VST plugin and standalone
  • Under $1,000 US

From a structural perspective, the synth looks something like this:

This differs from the typical analog synth architecture of mixing the oscillators together, and then sending them through a single filter and VCA, and then into any effects that may be included in that each “tone” is a complete polyphonic synth in its own right, complete with LFO, DCO, DCF, and DCA. In effect, three separate synths that can be combined into a final sound (or patch). Additionally, the oscillator from Tone 2 can be used to modulate the oscillator from Tone 1, and/or the two can be synced. This allows the creation of some very complex sounds with a lot of dynamics, depth, and motion.

There are certainly items on my list that could be superfluous or made redundant by use of a comprehensive modulation matrix. I could probably be just as happy (or happier, maybe) if the analog oscillators were replaced with well-engineered modern virtual analog oscillators such as those from Modal Electronics or ASM, and I could probably be happy with only two oscillators if the noise source is independent of the oscillators. An intelligently designed control matrix could reduce the number of knobs/buttons/switches required (and thus reduce the cost).

As I said, there’s nothing that I know of that completely fulfills my wish list, at any price, but there are a few interesting instruments on the market.

Roland GAIA SH-01

Roland GAIA SH-01

Eagle-eyed readers will recognize a lot of my druthers, as well as the block diagram above, come from Roland’s SH-01 GAIA, a synth with a brilliant concept that unfortunately doesn’t quite deliver sonically. When the SH-01 was introduced in 2010, virtual analog hardware synths didn’t have the oscillator resolution available today, and so there’s an inherent overall sizzly or gritty sound that just doesn’t quite sound analog. It stems from the fact that, for example, the digital waveforms generated were. I’m guessing that there’s just not enough DSP power under the hood to create 64-voices of buttery smooth waveforms — Roland may have been better off reducing the polyphony and putting less strain on the processor. There are a few other shortcomings of the hardware, such as the use of potentiometers instead of encoders or using “catch and latch” controls, that make real-time performance a little steppy and unpredictable, especially when trying to control specific parameters across layers. I suppose that some of this could be overcome with an appropriate MIDI controller. With work, some worthwhile sounds can be made with the SH-01, but at $750, it may be a bit more than I’m interested in spending on a synth that doesn’t stand up sonically. But it does set a bar for its innovative feature set. Interestingly, there’s also a multi-timbral GM2 spec synth under the hood as well, conforming to Roland’s standard GM2 MIDI channel assignments, so conceivably, a good MIDI controller could be added to the GAIA to have a fairly useable performance instrument. Also interesting is that my old Roland VR-09 had an SH-01 hidden under its hood, but only a very few of the controls were accessible from the front panel, and the rest could only be accessed via an iOS app.

Modal Electronics Cobalt 8

For about the same price as the GAIA, Modal Electronics offer the Cobalt8 (available as a desktop module for $100 less, or for $100 more, there’s a 61-key version). The architecture of the Cobalt is a little more “vanilla,” in that there are two “oscillator groups” that are mixed and fed through a 4-pole morphable filter and on to a VCA and finally effects. Cobalt’s virtual analog oscillators are top notch — even on the $220 Skulpt SE — which is particularly impressive for a digital synth (Starsky Carr compared the Skulpt’s oscillators to the Sequential Oberheim OB-6, and you can barely tell the difference), and modifiers within the oscillators can create evolving timbre changes without using the filter or any of the LFOs. There are three dedicated envelop generators (for modulation, filter, and amplitude) and three assignable LFOs (two of which are polyphonic), and there’s a fairly flexible modulation matrix. Conceptually, the Cobalt8 is quite similar to the Skulpt SE, but with twice the number of voices, somewhat greater depth to each function, and a far superior build quality. Additionally, the Cobalt8 and 8x have a very nice Fatar velocity-sensitive keyboards with channel aftertouch (37 keys or 61 keys, respectively) and all Cobalt models (and, in fact, all of Modal’s synths) support MPE and poly-chaining, and are compatible with MODALapp, Modal’s excellent multi-platform app/VST plug-in editor.

Limited Sky

Interestingly, paying more money doesn’t necessarily get your more capability in virtual analog synths. Instead, what you get is either a less capable pure analog synth or some sort of hybrid digital synth. That is, unless you pay a LOT more money, but even so, not everything on my wish list gets fulfilled.

With that said, there are some truly wonderful sounding synths when the price crosses the $1,600 boundary, starting with the 8-voice analog Sequential Prophet Rev 2, or ASM’s Hydrasynth Deluxe. Both are truly astounding instruments with depth that belies their relatively simple appearance. On the one hand, the Sequential’s sound is fat and warm and organic, while the Hydrasynth can produce some of the deepest, widest, and most interesting sounds I’ve ever heard.

I’m not sure at this point that I’d ever be interested in spending any more than the price of a Hydrasynth Deluxe or Prophet Rev 2. From what I’ve heard, I don’t think that you really get enough sonic value to warrant it, in most cases.

Some of you out there will tell me that I should be moving to VSTs and a computer-based setup, but I really would prefer to limit computer functions where possible to recording and mixing and mastering completed projects. Even after over a year with my Kronos, which is essentially a PC in a custom box, I’m not fully comfortable with a DAW-based system in any kind of live environment. And, honestly, I don’t think that they sound as good as even the $220 Skulpt SE.

What do you think?

I’d love to hear your thoughts. For some points of reference, I’ve provided some links to the various instruments I’ve mentioned. Am I out of my mind? Is analog or virtual analog a dead end, and wavetable synths are the future? Leave your comments below.