Review: UVI PX Apollo

A one-of-a-kind synthesizer brought to life in software
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Once upon a time, synthesizers could play only one note at a time. The quest to create a polyphonic synth—one that could play many notes simultaneously—presented first-generation synth designers with difficult challenges. One primordial polysynth was the Moog Apollo, a prototype instrument built in 1973 that two years later evolved into the desirable but notoriously unreliable Polymoog.

Late last year, French developer UVI converted a meticulously sampled collection of Apollo sounds into a software instrument that exceeds the original in every way. Like all UVI soundware, it needs host software to run—either UVI Workstation or Falcon.


Most people who purchase PX Apollo will run it on UVI Workstation, a Mac and Windows-compatible sample player that runs standalone or as an AAX, AU, or VST plug-in. Workstation is free to download, completely multitimbral, and includes dozens of outstanding effects. In 2013, the nonprofit Bob Moog Foundation acquired one of only three known Apollos with the goal of restoring and preserving it in their archival collection. Once it was cleaned and repaired, the BMF possessed the only known working Moog Apollo in existence. Foundation personnel then sampled it in painstaking detail, capturing every note of every preset numerous times to allow for round-robin switching when you press a key repeatedly.

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The BMF’s Apollo has 71 velocity-sensitive keys and 14 preset sounds. It also has 12 oscillators—one for each pitch in a single octave—and their frequencies are subdivided into enough pitches to cover the keyboard’s entire range, much like a Farfisa organ or ARP String Ensemble. It has a global filter, and you can split the keys to play bass with your left hand.



PX Apollo's Arp page supplies separate user-programmable arpeggiators for each oscillator. For PX Apollo, UVI created a graphical user interface that resembles the Moog Apollo’s front panel. It loads as a single UVI Workstation or Falcon preset, and you select the original master voice presets using 14 buttons, and load more than 150 UVIdesigned variations using a browser menu and scroll buttons. Although master voice presets are only numbered, the others are named and divided into 11 categories such as Sweeps, Strings, and Arpeggio. The GUI is scattered across five pages accessed with buttons labeled Main, Edit, Mid, FX, and Arp.

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The Main page displays two oscillators and a bass oscillator you can toggle on an off. Oscillator A plays samples from the Apollo sampling sessions, and Oscillator B generates 12 supplementary waveforms. Oscillators A and B each have their own volume, pan, resonant lowpass/bandpass/highpass filter, amplitude ADSR, and filter ADSR. Enabling the bass oscillator splits the keyboard. The bass oscillator has its own subtly resonant filter, but its only user control is cutoff frequency.

The Edit page supplies controls for oscillator tuning, stereo variables, and mod-wheel assignments, and FX accesses overdrive, chorus, phase, delay, and reverb parameters. The Mod page has a 4-waveform LFO and a 16-step sequencer for modulating oscillator and filter parameters (but not pitch), and the Arp page has controls for arpeggiator parameters, including two 16-step sequencers for velocity.

The 14 Master Voice presets perfectly capture the sound of the original instrument. One sounds rather vocal-like, two resemble strings, two are brassy, and two others resemble a harpsichord. The seven remaining timbres are not quite organs and not quite pianos. All are available in mono or stereo. UVI’s factory presets all begin with the original sounds but take advantage of the host’s architecture to make them more exciting, often with effects and arpeggiation.


Although I found PX Apollo’s sounds unique and useable, I experienced an aggravating problem running it in UVI Workstation. Whenever I changed presets or certain parameters and started playing within a second or two, the timbre was momentarily garbled. Changing the audio buffer size to at least 256 samples fixed the problem, but that introduced more latency than any of my other UVI libraries. Fortunately, I had no such problem in Falcon.

Nonetheless, I’ve really enjoyed having a piece of synthesizer history as another color in my timbral palette. The cost is quite reasonable, many of the sounds are unique, and its GUI makes using PX Apollo straightforward enough for live performance or studio work.


More consistent, more dependable, and more flexible than the original in every way. Includes dozens of new presets that incorporate the original timbres. Excellent price.


Limited velocity sensitivity range. Requires a larger buffer size in UVI Workstation.