Weston Precision Audio’s new module is called the Phase Animated Oscillator, aka the PAO, but just what exactly is a phase animated oscillator? There is a bit of physics to consider when thinking about the functions of this module, since we don’t have oscilloscopes built into our heads. Basically, when two sound waves are perfectly aligned, they are said to be in phase; they sound the same and there is no audible difference. The PAO has two oscillator output banks that allow the phase of a waveform to be shifted and modulated with the other, or animated, essentially, adding harmonics to create a more complex sound.
At its heart the PAO is a triangle‑core VCO with two sets of waveform outputs. The oscillator bank on the left is normal waveform outputs, and the bank on the right is the phase‑animated waveform outputs. Both waveform banks contain sine, saw, triangle and square wave outputs, but Weston have added two other unique outputs on each side. On the bottom of the module the left set of six waveforms is fixed at zero degrees phase, and the right set can be adjusted between zero to 180 degrees with a push‑button lock option at 90 degrees, which can be helpful for jumping to a phase.
Both sets of waveform outputs can work independently, but if both outputs are patched on each side it can create a waveform with more texture or even a stereo effect, depending on the way it is patched. If the output of the waveforms on the right is set to zero degrees, the waveforms will be the same and overlap. But at 180 degrees, they will be opposite and create a panning sensation. Though this is a single‑oscillator module, it can sound like a dual oscillator by mixing two waveforms from the left and right banks and slowly phase‑modulating the waveform on the right side.
The analogue sound is warm and clean, though the phase animation has the potential to create grit and harshness. It creates full and textured sound waves and therefore lends itself very well to panning and spatialisation. We hear two waveforms in phase when at zero degrees, and then the phase animation becomes audible as they are adjusted, slightly or drastically, to become out of phase. Then, there is the great CV experimentation point through the modulation inputs to be explored.
It’s when you introduce CV to the Linear FM, Exponential FM and Linear PM inputs that things start to get really interesting, creating all kinds of complex results. For example, if you send three different speeds of CV pulses to the three different FM inputs, the PAO can even create interesting rhythmic sounds. The second set of phase outputs can be modulated through‑zero with the Linear PM and Linear FM. To elaborate on the function of through‑zero, the phase of the waveform is reversed, the frequency is increased, and the pitch remains stable.
It sounds pristine and absolutely wonderful.
For the discerning ear, which as synth players I think it is fair to say we all have, it is helpful to try different combinations of outputs from the two oscillator banks and compare the sounds, 6x6 giving you 36 different pairings in total. For example, if you pair the triangle wave output on the left with the unusual MW output on the right, the knob that controls the phase modulation produces a filtered, harmonic sweep. It sounds pristine and absolutely wonderful. Though it does not go too deep, the manual is extremely helpful in explaining the functions of the PAO, as it contains figures of the oscilloscope to explain and help us understand the waveforms and their sums in various phases.
For those who want to get into creative waveshaping with modulation options and a full, textured sound within a single oscillator, the PAO more than justifies its 18HP of rack space.
£279$325