Cherry Audio’s Pentaphonic is a recreation of the Gleeman Pentaphonic, an early-1980s hybrid instrument that combined five-voice polyphony, three digitally controlled oscillators per voice, analog filtering and a built-in sequencer. It is out now for Mac and Windows at $59.
Cherry Audio’s own walkthrough with Mike Martin.
Why the original is worth reviving rather than merely remembering
The Pentaphonic sits in an unusual spot in the history. It was a genuine DCO-plus-analog-filter hybrid at the start of the 1980s, which puts it alongside the instruments that defined what polysynths would sound like for the rest of the decade — and it sold in tiny numbers, so it had no influence at all.
That combination is what makes a recreation interesting rather than nostalgic. A new Juno-106 plug-in competes with your memory of a thousand records. Nobody has a memory of a Pentaphonic, which means the instrument arrives as something to find out about rather than something to compare.
Two things about the architecture are worth drawing out.
Three DCOs per voice, in 1981-ish, is a lot. The contemporaries that mattered mostly gave you one or two. Three oscillators per voice across five voices is fifteen oscillators, each digitally generated and then run through analog filtering — a division of labour that is now completely standard and was then an expensive bet about which half of the signal path benefits from precision and which benefits from character.
The waveform set is not the usual four. The original had eight waveforms, including two called Complex 1 and Complex 2 — and Cherry Audio has retained all eight, those two included. A manufacturer-specific complex waveform is exactly the kind of detail that gives an instrument a voice and cannot be reconstructed from a block diagram. It is also the detail most likely to be quietly dropped from a recreation, so keeping it is the signal that the work was done from the hardware.
What has been added
Cherry Audio preserved the architecture and added what the hardware could not do. The additions worth noting:
- Polyphony from five voices to 2–16, with unison and mono modes
- Pulse-width modulation, a noise generator and oscillator sync — none on the original
- Two expanded modulation/LFO sections, and critically both can use the eight oscillator waveform shapes rather than the original’s single triangle-wave LFO
- A 2-pole 12 dB/octave filter mode and keyboard tracking, alongside the original 4-pole 24 dB/octave low-pass
- Velocity to filter and amplifier, plus channel and polyphonic aftertouch with 14 parameters available for keyboard-pressure modulation
- A modulation stick and assignable pitch-bend range
- A dynamic arpeggiator with Arp, Leap, Order and Random modes plus swing, chance and feel
- A syncable, transposable 16×4 polyphonic step sequencer with humanisation
- The Parameter Animator — a further 16-step modulation source for cutoff, resonance, oscillator pitch mod and oscillator gain
- 22 effects, up to five in a chain, alongside the original chorus
- 375+ presets across 14 categories, including the original 50 factory patches
The modulation change is the one that will actually alter what you can write with it. Going from a triangle LFO to any of eight waveforms — including two complex ones — as a modulation source is not a convenience; it is a different instrument. Complex waveforms as modulators produce motion that is neither periodic in an obvious way nor random, which is the region most hardware never let you reach.
Shipping the original 50 factory patches alongside the new ones is also the right scholarly instinct. Factory patches are the manufacturer’s own argument about what an instrument is for, and they are usually the first thing lost when hardware disappears.
The clear case, as a theme
Three interface themes recreate different stages of the Pentaphonic’s visual history, including black and transparent designs with adjustable opacity.
The transparent one is not decoration. The Pentaphonic is remembered, by the few who remember it, partly for a clear acrylic case — a genuinely strange thing to build a commercial instrument out of, and visually unlike anything else of the period. Making the opacity adjustable in software is a small, slightly absurd act of preservation, and it is the sort of thing that signals a recreation made by people who cared about the object rather than only the circuit.
Available as a standalone application and as AU, VST, VST3 and AAX, with full MIDI control, DAW automation and MIDI Learn.