Pitch-tracking itself isn't a particularly new process. It's usually achieved through something called phase-locked looping, which uses a phase detector and low-pass filter to keep an oscillator's pitch in step with the incoming signal. The Squaver P1 (along with the smaller, simpler ConVertor synth) uses a proprietary, patent-pending ACO developed by Sonicsmith, which promises to provide latency free, accurate tracking. It also produces the real killer feature here: the generation of 1V/oct CV and other voltage signals based on the processed audio input. These outputs, of which there are Pitch, Envelope, Expression, Gate and Trigger, essentially allow anything that accepts CV input to be controlled by a mono audio signal, via the P1. What's more, the P1's numerous modular-friendly inputs mean that its ACO, VCA and VCF can also be controlled by external gear.
The Envelope itself can be set to either 100% positive or negative, or a blend between the two. Moving the Envelope Amount knob to the 12 o'clock position results in a square or "no envelope" setting. The SRC Mix knob allows you to blend between the dry source signal and the synthesised output, which is useful for adding just the right amount of spice to your incoming audio. The Sub Mix function offers similar control over the balance between the original ACO signal and a square wave sub. The sub is applied between one and two octaves below the ACO's signal. It lends some necessary weight to proceedings—sometimes the signal sounds a little anaemic without it.
If it's accurate pitch-tracking you're after, the P1 has you covered. The ACO operates between 25Hz and 6.4kHz, meaning it should be able to pick up almost anything you chuck at it. The two input filters help to improve tracking by narrowing down the incoming signal. One is a 12dB high-pass filter with stepped settings of 16Hz, 60Hz and 80Hz, while the other is a sweepable, auto-adjusting low-pass filter that automatically tunes itself to the fundamental frequency of the audio input. Between the two, you'll easily be able to zero-in on the frequencies that you're after.
For some users, a super on-point pitch-tracking synth isn't hugely exciting. But the P1 is at its most fun when attempting to deal with difficult source material. High-transient sounds like drums can often struggle in regards to pitch-tracking as there isn't usually enough time for the oscillator to determine the pitch before the next note takes place. Although the ACO in the P1 generally does a fine job, accuracy still tends to vary. It's these occasional misinterpretations that I found most enjoyable.
What follows are demonstrations of some of these idiosyncrasies and the available CV routing options. We've got the ever-reliable Make Noise 0-Coast on hand to provide all the CV-related ins and outs. For this first example, I'm using a Grand Piano instrument in Ableton Live, which sends some simple arpeggiated notes into the P1's input. This sets off the ACO and starts generating noise (as well as CVs). The 0-Coast's Random output is attenuated before being sent to the P1's VCF input, while its Slope circuit output is sent to the P1's Gate input. In the video below, the Envelope Amount is blended from 100% positive to 100% negative, followed by turning the Octave knob from -2 to +2. Then I slow the rate of the 0-Coast's Slope section using the Fall knob while adjusting the P1's filter cutoff, which is on a low-pass setting.
In this final video, I wanted to use some of the P1's CV outputs to control the 0-Coast. You can hear the clean drum loop being sent from Ableton directly into the P1. The Pitch and Gate CV outputs are patched to their respective inputs on the 0-Coast, which is set to its default, normalised setting. Over the course of the video, the clean signal from the P1 fades into the 0-Coast's output. What you are then hearing is how the P1 has interpreted the incoming pitch information from the drum audio and converted that into CV and gate information for the 0-Coast to respond to. The drums are fairly harmonic in content, so beyond the basic rhythm there are some tonal similarities, but it's interesting to hear the extra bits and pieces added in by the conversion. Opening up the P1's low-pass input filter allows for more audio content to be converted to CV but, as you can hear, things get messy pretty quickly. I bring the input filter's cutoff back down, finding a nice sweet spot while tweaking the Multiply section's CV Input Attenuator knob on the 0-Coast to bring out some more harmonics.
If you're particularly into screeching abstract noises, the Squaver P1 will be especially appealing. If you're looking for a subtler option, then the ConVertor, also by Sonicsmith, could well be worth a look. It loses some of the P1's synth controls (including the sub oscillator, sadly) and CV inputs, but most importantly retains the Eurorack-friendly CV outputs at a significantly cheaper price. However, if the sound of audio-controlled synthesis sounds appealing and you happen to be in the market for a new particularly weird mono synth, then I reckon Squaver P1 is the way to go.
Ease of use: 4.0