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what exactly makes up a complex vco?
MUFF WIGGLER Forum Index -> Modular Synth General Discussion Goto page 1, 2  Next [all]
Author what exactly makes up a complex vco?
smonkey
What exactly makes up the ever popular "complex vco".

Seems like more and more things are called this but I'm not entirely clear on
what it means.

Or am I missing something, is it just a vco with a lot of bells
and whistles in a generic fashion?

Or is it some particular way of treating two vcos together
to get interesting normalized setups?

(please feel free to point out threads that are germane, but with
such simple search terms I came up with too much noise).

(also, if it is indeed some particular magic vco, then is there a vco + X combo that would make one?)
Kent
The core of the idea comes from Don Buchla's original "Programmable Complex Waveform Generator Model 259". Please see the printing along the top of the module:



The consensus (based upon released modules claiming to draw from the "Complex Oscillator" heritage) is that there must be a minimum of the following in one module:

• 2 oscillators
• A modulation buss with VCA between one oscillator and the other. There are usually a few routing options on offer, but the minimum offering must including pitch modulation.
• Some kind of waveshaping available on the output of at least one of the oscillators. This is most likely to be found on what is called the "Principal Oscillator".
mskala
I want a complex oscillator with real and imaginary parts. And that's not a joke - quadrature outputs are really useful for pitch and phase shifting and I'm surprised there aren't more modules offering such.
J3RK
I agree with the above more or less.

I would say there are a few ways you can go about having a complex VCO. One way (at its simplest form) is to have a dual VCO with multiple ways to combine, modulate, or shape the output(s). So as in the Buchla, a primary VCO (possibly with extra wave shapes and modulation inputs,) and a secondary, (that could be simpler,) that can be used to modulate the first. This would be it at its most basic form I think. Being able to sync or lock phases in some way, and having a modulation index VCA are nice features as well, so you don't just have a lot of random modulation. You can output something that can maintain a pitch relationship. (not that this is always wanted, but I think is kind of integral to this sort of thing)

Another way would be like Grant Richter's Waveform City. It's an analog VCO, which has digital wavetables that store the more complex waveforms, that with the other style, you might have to carefully dial in modulations to get close to. So you could also lump other wavetable type oscillators into this category. SynthTech, Intellijel, Harvestman, etc.

I think that basically anything that outputs a waveform that is more complex than your typical saw, sine, triangle, pulse etc. falls under this category. Having the second VCO, a VCA, etc. is bonus material. w00t
Navs
Historically, Buchla.

But once you try to pin it down it's cobblers e.g. I would be tempted to follow J3RK and say 'anything other than a simple saw etc.' Well, what about a saw through a highly resonant and unstable filter? And what if our complex waveform is static - a sine directly into a wavefolder, rather than dynamically through a VCA - it might as well be a boring sawtooth, right? So, it's just a module with lots of other modules tacked on to it, right? Yeah, I've got one of those. It's called a modular synth. razz
sduck
Navs wrote:
So, it's just a module with lots of other modules tacked on to it, right? Yeah, I've got one of those. It's called a modular synth. razz


^^^this. Most of us already have a collection of complex oscillators, we just don't call them that.

J3rk was being succinct, but I don't mind pointing out that he designed a really fine CO - here's my version of it -



You'll note that all the stuff is brought out to patch points - no pre-patching here. So you can build up whatever flavor of CO you want. And if you're like me you'll be wiggling away at it, and think to yourself "self? it sure would be nice if these vcos had some kind of sync" and then you can just sub some kind of vco that has sync. Or you can sub a teezer for some through zero modulation fun. The possibilities are mind boggling!
mritenburg
Navs wrote:
So, it's just a module with lots of other modules tacked on to it, right? Yeah, I've got one of those. It's called a modular synth.


It is also one of the core distinctions between East coast and West coast methodologies. In classic West coast, the Complex Osc, with a wave folder, fm, am, etc controls the harmonic content of a wave instead of resonant low pass filters as is the norm in classic East coast.
J3RK
Hmmm... twisted How about a single VCO with a single V/Oct input, and a single signal output, with only a pitch knob and a "Complexity" knob.

Turn up the complexity knob, and your waveform gets complex. No idea of what's actually happening behind the scenes. (internal linear cross mod to an invisible second VCO, sync, and folding. Maybe some digital wave shaping...) Mr. Green

I may have to build one just to be a Nutter!
mritenburg
J3RK wrote:
How about a single VCO with a single V/Oct input, and a single signal output, with only a pitch knob and a "Complexity" knob.


You just partially described the Richter/Wiard Anti-Oscillator.
J3RK
hehehe I didn't think about that. I love the Anti-Oscillator too. It's one of my favorites. To be fair, it does have slightly more of a UI than I described, but... hihi The funny thing is, or maybe sad that my brain didn't make the connection right away, is that while I was typing that post, I was thinking to myself, "hehehe the antithesis of the complex oscillator" Mr. Green
Randy
sduck, is that Euro? It's amazing!

Randy
sduck
Mine's 5U MOTM format. There's a euro version available from synthcube, but it looks like they're out of stock currently

Randy
The Euro version is too big for me (and out of stock, you're right about that). I like yours, compact, nice design.

Randy
J3RK
There should be more at Synthcube soon. There were some repeated delays some my fault, some manufacturing. They should have received what they were waiting for today.

w00t
ndkent
The term probably comes from Buchla lust. Buchla used the term on the 259. The original is scarce, expensive and since it has a normalized modulation oscillator built in, certainly does much more than a non-complex vco or 2 for that matter. But of course it's not a small proposition to get a costly original or a new 200e or a clone of the Buchla... especially if you don't have a Buchla system and happen to like your current system.

I would say one way of looking at it is the term has more or less evolved a little to include anything that does a more complex waveshape than the standard ones... umm and perhaps gets bonus points if it seems a little reminicent of Buchla in some respect but is not essential.
lvoemachine
I'm impressed by how small Sduck made that layout. I personally like a bit more space when working (it's why I use MU anyway) but your stuff is always SO GOOD and the color infills rule. makes that grid way easier to dissect to my eyes.
infradead
sduck's panels are fucking gorgeous
fac
It's a VCO that has an imaginary part. Kind of like vaporware.
ym2612
I think usage of the term has become a little loose. For me it refers to the normalled 208/259/261e mod/index vca/primary/waveshaping/timbre arrangement, or a set of modules that make up the same feature set.

I'm more keen to describe oscillators that do more than basic waveforms in specific terms. A Rubicon is a VCO with TZFM, FM index VCA, and suboscillator. E350 is a wavetable osc. Braids is a multifunction digital osc. An Anti is a VCO with waveshaping and internal self-FM. Etc.

DPO, Verbos, Furthrrrr, Synchrodyne+expander, J3RK Mirror Core, Hertz Donut, and even Pitts Generator+expander fit the bill, I think. But that's not to say that other VCOs are "not complex" or worse somehow. It just describes a specific design influence.
Rod Serling Fan Club
Judging from the euro forum, the definition of "complex oscillator" is any oscillator someone currently wants, that has more than 2 wave forms.
giftculture
sduck wrote:
Navs wrote:
So, it's just a module with lots of other modules tacked on to it, right? Yeah, I've got one of those. It's called a modular synth. razz


^^^this. Most of us already have a collection of complex oscillators, we just don't call them that.

J3rk was being succinct, but I don't mind pointing out that he designed a really fine CO - here's my version of it -



You'll note that all the stuff is brought out to patch points - no pre-patching here. So you can build up whatever flavor of CO you want. And if you're like me you'll be wiggling away at it, and think to yourself "self? it sure would be nice if these vcos had some kind of sync" and then you can just sub some kind of vco that has sync. Or you can sub a teezer for some through zero modulation fun. The possibilities are mind boggling!


Wow, this looks amazing! Are there plans / pcbs / panels for this, or did you do this as a one-off?
sduck
Holy necrobump Batman!

That was a one-off. I hope to never do that wiring again. The PCBs are available, and my panel design is free for the asking, so you could go do it yourself if you were so inclined.
wsy
ym2612 wrote:

DPO, Verbos, Furthrrrr, Synchrodyne+expander, J3RK Mirror Core, Hertz Donut, and even Pitts Generator+expander fit the bill, I think. But that's not to say that other VCOs are "not complex" or worse somehow. It just describes a specific design influence.


Hmmm.... Synchrodyne+expander as a complex oscillator.... you know, I never thought of it that way, but hmmm.... you may be right there.

Just seems a little odd that your oscillator core is a self-resonating filter.... or more odd that it's not a normal SV filter or even ladder filter,
but a switched-capacitor filter. But yeah. You have a point there.

Viva la Difference!

Oh, and a Kermit also fills the bill - two oscs, with two cross-modulation busses, and both oscs have wavewarping. Just because
it's digital and can do tap-tempo and is sorta kinda oriented to CV doesn't mean it's not a complex oscillator - in some ways more
complex than it's big brother, the Hertz Donut.

As to a "complexity" knob - thru-zero phase-distortion feedback is pretty darn close to that behavior. From pure sinewave to what sounds
pretty much like broadband noise.

- Bill
ioaek
nice job on that panel design, wow
giftculture
sduck wrote:
Holy necrobump Batman!

That was a one-off. I hope to never do that wiring again. The PCBs are available, and my panel design is free for the asking, so you could go do it yourself if you were so inclined.


Yeah, sorry for the necrobumpage, I just recently picked up a shapeshifter and so I have been plumbing the depths of muffs looking for info on complex oscilators wink
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