Modulation 'Masterclass'

First of all, I put 'masterclass' between quotes because I am not a master. I can call myself an 'expert' after +10.000 hours of patching but that's no guarantee for good information. However, you wouldn't be interested in watching modulation basics either. So my 'masterclasses' are more like sitting around the campfire, telling ghost stories, and we're all equal. It's just me telling the stories and it's OK if none of them are true.

I've been inspired by a subscriber, who pointed to his beloved Rossum Trident/Triton as his/her/their favorite VCO. I looked it up, decided there's too much overlap with my THREE-BODY VCO, but noticed something interesting called 'Zing modulation'. It's a recipe based on ring modulation, with the simple trick of syncing the carrier and modulator. Dave wrote he may have been the first person who ever used the term 'hard-sync', but credited the technology to Serge Tcherepnin. Suddenly I was lost and inspired in a new world of modulation I did not know about. Since it's a recipe instead of a circuit, we can all use it as long as your VCO has a Sync input, and you have a ringmod in your case. If you don't, get one. It's an essential piece and it costs nothing.

I can't explain Zing modulation (ZM) without Ring modulation (RM) without thru-zero amplitude modulation (AM) and when the bloody TZ comes along I am aways reminded that I am still clueless about thru-zero FM. I've seen good, bad and no explanations about TZFM. I know it preserves pitch, it's been restricted to digital - but now it's also possible with analog - and it needs to be supported by the VCO. The biggest enigma (for me) is, if it preserves frequency and pitch quality to the highest degree, how can it be frequency modulation?

You can't seem to patch it up, the VCO should do it. I have a problem with things that can't be done. It's not that I am stubborn, an important aspect of creativitiy is to never give up. And to be confident you'll figure it out eventually. Thanks to Dave Rossum's recipe, I wondered if I could ringmod my modulator VCO before it goes to my principal VCO's LIN-FM. It can't possibly be amplitude modulation anymore.
I experimented with ring-modulating the modulator with an inverted version of itself (inversion is not important, a copy also works), so it would go thru-zero-by-itself. I don't know if this qualifies as true thru-zero so I call it WTFM.

Anyway, this video can keep you busy for weeks. Happy Patching!
Robert.

00:00 Intro
00:52 Amplitude Modulation
01:44 Frequency Modulation
02:47 Ring Modulation
04:12 Zing modulation by Dave Rossum
04:52 Thru-Zero Linear Frequency Modulation
05:59 Thru-Zero Linear WTF Modulation by Cinematic Laboratory
08:17 A few Ring Mod alternatives
09:32 Zing along with Serge and Dave

[CinematicLaboratory]

I finally figured out how TZFM works, thanks to mr. Jason Lim from Instruo. You need to see it happen to understand it. I am going to revisit the subject in a few weeks. It's actually very simple as a technique, but not so simple to make it happen in a patch. When a VCO goes through zero, a frequency - let's say 440 Hz - drops all the way to 0 Hz, and then flips to negative 440 Hz where the waveform is inverted. Then it goes all the way up to positive 440 Hz again, crossing 0 Hz. So it's not just inversion, it moves the pitch all the way down, stalling the VCO in between. In analog, the TZFM principal sticks to a fixed frequency, but the modulator will change pitch while it moves 'through zero' with different speeds. So the traditional roles of principal VCO and modulating VCO are swapped (in analog). Digital VCO's can do the math internally and can remain principal/carrier. I'll keep you posted and make some cool graphics again.

[malwida]

How on earth are you churning out these deep videos in this frequency lately? Every day another gem!

[_grossy]

Love this masterclass style video - more please!

[KenSwanson-pi]

That collection of sound, at the end .. is especially ear pleasing.

[truhhimself]

another fun thing to try if you don't want to synch the oscillators but want a more (pitch) stable sound is to patch up a phase locked loop (or something a bit like it. it works well enough even if you just ring modulate modulator and carrier and use that to fm the modulator)

[electricdawn]

You need a VCO capable of Through Zero FM. All it means is, that you can modulate a VCO so it STANDS STILL, effectively producing DC voltage at 0Hz. You can also "negatively" modulate it, but all that this means is, the further negative you get, the more the frequency ramps up, just like when you go positive.

[hoofjaw]

I think maybe you can patch TZFM with a non-TZFM oscillator (and some other modules). Might this work? Take an output (the sine wave if we are keeping it traditional) from what you are going to use as your 'carrier', mult it and invert one copy. Patch the non-inverted copy (from the mult) and the inverted copy to the inputs of a voltage controlled 2 to 1 switch (you'd want a switch that switches momentarily according to gate signals - so not set to latching if it had that option). The output of the switch is what you will be monitoring. Now take the output of your 'modulator' oscillator and mult that. Patch one copy to the LFM input of your 'carrier'. Patch another copy to the signal input of a comparator. Set the comparator threshold to 0V. Patch the comparator out to the switch's CV input. Ideally, you would have the non-inverted carrier output side of the switch active when the comparator output was 'on', but it doesn't really matter, I don't think (it would only be like inverting your modulator signal in a normal TZFM patch). If you don't have a VC switch a couple of VCAs (and a mixer) could be used (you'd need to also invert and offset (or NOT) the comparator out to control (the second) one of the VCAs). I'm not sure if perhaps you might need to be also inverting the modulator at the same time as the switch switches to the inverted carrier out if so you'd need another switch and a bit more multing. And it probably still won't work!

[jonaseggen]

For anyone with two analogue filters, using the resonance on one filter to modulate fm input of the other is fun.

[rolf-dieterlieb]

Hi, analog TZFM is possible, if 1st the carrier VCO supports it and 2nd the modulator VCO has bipolar waveforms (If not, try to invert it 🙂). Examples for analog TZFM-VCOs I have good experience with are Joranalogue Generate 3, Patching Panda Operat or Shakmat Banshee Reach. However, those do not sound like a digital Yamaha TZFM. I discussed the reason once with Dieter Doepfer who explained, that the influence of the amplitude of the modulator in Yamaha TZFM is much larger (around 8 times!) on the carrier than usually possible in analog circuits.
By the way, with small amplitude amounts in LinFM the signal freq. is kept, because the mean of the positive and negative lin FM is still the original frequency. This is independent of the possibility of TZFM. If the negative lin FM effect reaches 0 Hz a non TZFM VCO would stop, a TZFM VcO will be able to restart with increasing frequency but different sign of the amplitude. In this case the mean of the freq is no longer the original frequency unless this is set to 0Hz (hence the other commentary on Neoni). As I find too long commentary boring, I will stop here. If you are interested in further technical details or PM matters, please feel free to contact me directly...

[tgiencke]

The hard sync FM is a cool one. I am going to have to try with the Matriarch and also apply the techniques of the Digitone.

[studionl]

With TZFM the carrier and modulator swap. The modulator needs 1v/oct in, while the carrier should be set to 'dead zero'. At least this is for the Doepfer A-110-4. Jason has a very good explanation with the Instruo Neoni!

[quantickjumps]

TZFM on the Rubicon 2: "Turn on the LOCK switch (which sets Rubicon2 to a perfectly symmetrical and pitch-corrected state) and listen to the same Triangle Wave output — the sound you now hear is TZFM"

[lesynthlofi]

Ace video, as usual! 🔥
Never heard of Zing modulation! Will try later today on my Matriarch.
BTW, I think for Through-Zero to work, the carrier oscillator needs to have the ability to interpret negative values; if it’s not built-in, you can’t patch it. (I think you said that in your video already, mind you. Must be my mind doing some TZFM on my cells…)

[goonfish]

Which module were you using for that master reverb throughout?! 🤤 As usual, I left with a slightly heavier brain and some new patch inspiration!
Lovely tones in this one, especially the softer-sounding ones.

[isaacc]

So why do you consider Serge a guilty pleasure? Do you have naughty thoughts while using it?lol