3 new Instruo hardware modules

Hope these make it to VCV Rack. Just saw this on mod wiggler…


I don’t understand the verbiage from the through zero VCO. “Unlike traditional FM, where an oscillator momentarily stalls as negative voltage pulls its frequency down to 0 Hz, neóni inverts the polarity of its waveforms until positive voltage pulls it back through 0 Hz”

That doesn’t sound like FM at all - more like AM. I’m sure it sounds good, but is it misleading to call it “FM”?

Btw, the “Kitchen Sink” VCO has many of these features (sync, wavefolding, waveform options).


I think he’s essentially saying the same thing about through zero FM as Omri describes in this video no?

“With through zero FM, the wave will reach zero, stop, and everything past the zero point will be inverted and will start speeding up again”

I didn’t understand it either, but maybe it’s just because I don’t understand what a “through zero VCO” is.

Does that mean that the modulator internally is routed through a full-wave rectifier? I.e. turning the modulator from a bipolar signal into a purely unipolar signal?

Watch Omri’s video, he explains pretty clearly what through zero FM is, compared to regular FM - complete with diagrams - and a through zero VCO is a VCO that does through zero FM (or PM)

I believe a full wave rectifier is involved but I couldn’t say any more than that with any confidence.

Bottom line is that a through zero VCO allows for maximum amount of frequency modulation and timbral change while keeping the pitch stable.

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I watched the video now. The demonstration is very clear - why through-zero FM is better than linear is better than exponential for purely musical results, so that’s great. However… I must admit his explanations are word-salad in my ears a lot of the time, mixing up concepts etc. Maybe my brain is just wired differently, dunno. I would love to read a really accurate and technically grounded explanation for it.

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No, that not how I read it. I read as output = carrier if modulator is positive. Output = -carrier if modulator is negative.

I don’t see anything wrong with how Instruo describes the module. It matches my understanding of TZFM. On a standard oscillator, if you feed a sufficiently negative voltage to frequency then the frequency becomes zero and the oscillator won’t respond to voltages below that (it “stalls”). Put another way, the modulation voltage is rectified when it becomes sufficiently negative, resulting in inharmonic sidebands when modulating at audio rate. This might be desired behavior when synthesizing drum sounds but in general it’s not what you expect from FM synthesis.

A TZFM oscillator fixes this by inverting its phase when the frequency goes below zero, i.e. frequency minus f is the same as frequency f except that it’s phase-inverted. This gives sidebands that are harmonically related to the two oscillators in the expected FM synthesis fashion – Bessel functions & so forth (which is why the module’s description says “less clang, more bang”).

This isn’t anything to write home about for a digital oscillator but I think it’s rarer for an analog oscillator, which is why they drew attention to it. Analog TZFM sounds different than digital TZFM (compare eg any modern digital FM synth to Frap Tools Brenso).

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But it says “unlike traditional fm”, and then describes traditional tzfm. So I think it is saying “we don’t do traditional fm, we do something else. But maybe I’m wrong. I just don’t understand it, and that’s ok.

I think that is referring to not-through-zero fm as “traditional”.

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Yep - traditional FM = Linear or Exponential (and not TZFM)

ok, but when Chowning “invented” FM in 1967 is was digital and it was “through zero”. I guess analog people came along and did the same thing in the 80’s or 90’s and called it “traditional”.

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yeah, I don’t think they mean “traditional” as in oldest pedigree, but as in most commonly practiced. it’s just a product description. I wouldn’t parse it too diligently. it’s just marketing balls.


hey, were these accidental leaks? is someone getting fired? the moog audio pages are down

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It looks like it. They’re not on Instruo’s own page and nowhere on the Internet or YouTube. So probably a premature leak/mistake. But the Neoni sure looks interesting…

I think this is through-zero in the usual sense for analogue oscillators. And differs from Chowning’s through-zero, but gives a similar set of sidebands, and therefore a similar kind of sound.

Has anybody contacted them yet to ask if their modules will make it to V2?


Good question. I hope/think that VCV will/have reached out to the commercial hardware co. that have vcv rack versions. It can only benefit them to have “preview” versions of their hardware available for people to try out. I have watched a few eurorack demos/tutorials on yt where they mention that there are vcv-rack versions so people can try before they buy.

I think I am more worried about plugins where there is less incentive for the dev to update but it is also a closed-source project. We might lose some of those.