Make Noise’s new analog oscillator is available in stereo: XPO, Stereo Prismatic Oscillator
Make Noise, the makers of analog synths from North Carolina, have always had a penchant for the chaos generated by wild, woolly tension. And their new oscillator has all the complex modulating, wave-bending trimmings. But now, as with their latest filter module, these sounds also fill your stereo field. It’s almost as if we have two ears instead of one.
The XPO, aka Stereo Prismatic Oscillator, has been gradually unveiled over the past few days. As an oscillator, you get the usual sine waves, triangle waves, sawtooth, sub-octaves, and what Make Noise calls “peak waves” (think thin, resonant, lots of harmonics of higher order). And then you just add a ton of modulation, FM, wavefolding, the works.
This was the case on Make Noise’s high-end and stupidly deep DPO synth module – a kind of complete synthesis lab masquerading as an “oscillator module”. So how does Make Noise top it? By switching to stereo, with the XPO and their recent Stereo Filter, the QPAS.
If you want mono, it’s there – via the left output modulations. But the XPO oscillator module and QPAS filter let you work in the stereo domain with all the fancy modulation control that draws people to modularity in the first place.
Feature set – the trick here is the ability to do Pulse width modulation in stereo, more Vari-Timbre in stereo (animating the waveform through the stereo field), and stereo wave bending (ohhh yes):
Stereo analog VCO with eleven simultaneous outputs (five mono outputs and three stereo pairs)
Modulate timbre via stereo pulse-width modulation, stereo vari-timbre, and stereo wave bending
Sine, Triangle, Sawtooth, Spike and SUB mono outputs
Single mono versions of all stereo waveforms via left output normalization
Modulate left and right channels together or separately with normalization and attenuators
The Center parameter adds additional timbre control to both sides of the Vari-Timbre and Wavefolded outputs
The linear FM bus features voltage control over FM depth and SUB to FM input normalization for easy GROWL.
Hard SYNC circuitry
Two 1v/oct inputs for transposition, melody stacking or the richest FM
Expo FM input with attenuator
Designed to pair well with QPAS, Mimeophon and X-PAN
Also check out this QPAS filter ($379, available now) – it’s four filter cores with “multi-peak” stereo operation:
Pricing and availability on the XPO are yet to be announced as of this writing, but a new DPO will set you back $599 USD.
I have a good idea of how it would sound from Tony’s description (hey, I’m a big word person), but there will be soundbites premiering later today on July 20 (if you read this earlier):
And just in case you want to read it in CDM’s font instead of what’s on Make Noise’s site, here’s creator Tony Ronaldo with some stereo thoughts. It all started with Tom Oberheim’s OB8. I’m the one pointing out…
The History of the XPO by Tony Rolando
I was lying awake in my bed at 3 a.m. thinking about music and synthesizers, that early morning precisely, the vocal pan of OB8. So simple, so effective. A bank of 8 analog pan-pots are nestled into the side of the instrument to allow the musician to choose the exact placement of each voice in the stereo field. When you play the instrument, notes may dance around your head. This got me thinking about how Oberheim and most other synthesizer designers of the 70s and early 80s primarily used pulse-width modulation for waveform animation. Don Buchla’s wavefolding techniques hadn’t caught on. The PWM has been more or less the same for decades and there is not much difference between the PWM from instrument to instrument. Some allow you to modulate further than others. A few even allow you to go to 0% or 100% width. PWM was typically generated from a Saw or Triangle Core, and while I tend to prefer PWM generated from a Tri-Core, the difference is subtle. The biggest difference is the filter that follows. PWM has a way of tickling the resonance of a filter that can really bring the sound to life.
This got me thinking about stereo filtering. How could a synth sound more stereo? At Make Noise we have vocal panning with the XPAN, stereo filtering with the QPAS and stereo echo verb with the Mimeophon. Surely that was enough stereo modulation.
Then it occurred to me, why couldn’t the PWM be stereo? This would be very effective in creating a stereo image since the left and right amplitude would be almost identical, while providing dramatic stereo timbre changes. I figured someone had probably done Stereo PWM before. I needed to research this idea. So I wrote about it in the notepad I keep on the nightstand and ended up going back to sleep.
I woke up the next day and immediately saw the note, tried to read it…
It was very difficult to understand what I had written, but it seemed that he was saying:
“The planets of our solar system, incineration. Like flaming orbs, Sigmund. After a cup of coffee, I was finally able to figure out what the note actually said.
“What could make QPAS and Mimeophon even more stereo? Stereo pulse width modulation? »
I spent the day researching stereo pulse width modulation. I did not limit myself to modules. I’ve read synthesizer manuals from the 70s to the present day. I haven’t found anything like it. Maybe there was a reason he didn’t exist yet? Maybe the stereo timbre modulation before a stereo filter and stereo DSP was just too stereo.
It seemed worth at least exploring, so I built a circuit to test it. The sound was ok, it was definitely stereo, but it wasn’t amazing. I patched it in the QPAS. It deepened the stereophonic effect of QPAS significantly. Both pairs of filter cores had their resonance peaks excited independently. I also felt very connected to the modulation of the stereo field. All of this came without having to worry about tuning between two oscillators.
So I turned to our STO for more inspiration. I tried the Variable Shape STO circuit in stereo and it sounded good, but it could be quite unbalanced left to right as it was modulated. I redesigned the circuit to compress the sound to make it more balanced. I called the new circuit Stereo Vari-Timbre.
I tried stereo jagged animation and it was less effective. The sound was very balanced (like PWM) but it wasn’t as dramatic and powerful. Also, it took a lot of analog circuitry to create the effect. I figured if I was going to put that many pieces on the design, I might as well turn to the DPO for inspiration. Stereo wave folding! It was wonderful, especially when integrated with the QPAS.
The stereo VCO was a new or at least uncommon concept, why not tie it into an existing frame to ease the learning curve. I turned to the QPAS to conceptualize the user interface. I figured if someone could learn QPAS stereo VCF they could use similar techniques for modulation of a stereo VCO. The QPAS form factor of the dedicated left and right modulation parameters normalized from left to right. Height control in the middle. Stereo outputs along the right side, to be in line with the QPAS stereo inputs. Then there was the QPAS “Q” parameter.
I wanted the XPO to have a central setting. Something that changed both sides of the sound simultaneously, just like the “Q” parameter on the QPAS does. The nice thing about the Q parameter is that it affects ALL 4 cores of the QPAS. The central parameter was to vary the mono waveform in a way that would make the stereo wave-shaping circuits that follow it even more interesting.
It was easy with the Stereo Wavefolder because I already had a unique circuit to do it in the DPO. DPO’s Shape parameter was excellent as a central parameter.
For the Stereo Vari-Timbre I looked to the STO, but there was nothing that would work as a central parameter. So I looked beyond the STO to the modules that inspired and informed it. The first Buchla 158 and 258 oscillators where they allow a crossfade between Sine and Saw. It’s such a simple circuit, but it sounds so good and it’s extremely useful.
The Stereo PWM channel that sparked this whole plug-in idea didn’t conform to the Center setting. I struggled for months trying to find a way to modulate the PWM circuit through the Center. Everything I tried was either overly dramatic, making PWM more PWM, or easier and better done with commonly existing modules. I finally convinced myself that having a set of outputs that isn’t influenced by the Center parameter might be functionally advantageous. You can modulate the audio frequency (FM) in the center and get more harmonic-rich folds while leaving PWM away from those harmonics, for example.
With the stereo elements designed, I still had plenty of space. I put in as many mono waveforms as possible. Since I had to create many waveforms to do everything I wanted to do with the stereo outputs, I had plenty of choice. I feel like having many waveform outputs available simultaneously increases the functionality of the module exponentially. Covering standards, SINE, TRI, SAW… I did a more traditional SAW as opposed to the weird DPO choppy SAW. I thought you might get something like this from the Vari-Timbre outputs. Instead of square I added Spike, as it is a less common waveform and also works great with a BP filter as found in QPAS. Again looking towards the STO, I put a declination of the SUB.
Like Flaming Globes, Sigmund.
Will be watching/listening for this one.