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"What the $#%$ is a Rungler?"
MUFF WIGGLER Forum Index -> Modular Synth General Discussion Goto page 1, 2, 3  Next [all]
Author "What the $#%$ is a Rungler?"
I thought people might be interested in this. I don't think its been posted before. It is extracted from a document written by Rob Hordijk, sent to me by Joker Nies. I hope and assume it is fine with Rob for it to be posted here:

"What the $#%$ is a rungler?

The purpose of the rungler is to create short stepped patterns of variable length and speed. One could categorize the circuit somewhere halfway between a plain S&H and a shiftregister-based pseudorandom generator. It needs two frequency sources to work and basically creates a complex interference pattern that can be fed back into the frequency parameters of the driving oscillators to create an unlimited amount of havoc.

The rungler is basically a CMOS shift register clocked by one oscillator and receiving its data input from the other oscillator. The output bits of the shiftregister are used as a binary code 'to do something with'. E.g. in the Benjolin the last 3 stages of the shift register for a 3 bit code that is fed into a 3 bit DA converter. This DA eight level output voltage is fed back to the oscillator frequency control inputs. The output of the DA is the 'rungler CV signal'. To describe the rungler waveform in similar terms as like a sine wave or pulse wave I call it a 'stepped havoc wave'.

When the rungler signal is fed back to the frequency parameters of the oscillators it will change the triangle waveforms and pulse widths of the oscillator outputs, making other types of havoc waves, like a 'pulsed havoc wave' and a 'sloped havoc wave'. Note that it is these properties of stepped, sloped and pulsed that are of interest in the waves.
(The Dutch composer Jan Boerman formulated an idea in the 1960s about audio signals that are inbetween pitched and unpitched. Havoc waves are probably somewhere in that region, maybe a bit similar to granular synthesis stuff. I haven't really thought deeply about this myself, but Boerman has certainly always been an inspiration to me to try to go into that inbetween territory.)

The rungler will try to find a balanced state. In this way it behaves according to principle from Chaos Theory. There seems to be an unlimited amount of possible balanced states and when a balanced state is just slightly disturbed it can be noted that it takes a little time to find the next balanced state, with noticeable bifurcations, etc. Note that a new balanced state is defined by the exact position of the control knobs plus the previous state it was in.

The first rungler experiments I did were back in 1980 I think, and there are quite a lot of variations possible on the rungler idea. In the Benjolin design the data input for the shiftregister is not just the pulse from the second oscillator but the XOR of this pulse and the last bit of the shift register (inspired on the pseudorandom generator). The XOR is the transistor/opamp combination that actually forms a controllable unity gain/minus unity gain amplifier, a very simple ringmodulator, so to speak.

Tip: An interesting option is to feed the three bits at the end of the shiftregister into the 3 'selection' inputs of a CMOS 4051 eight-to-one/one-to-eight analog switch and e.g. quickly switch between eight audio signals. You can take these three bits from the pins 2, 3 and 12 on the 4021.

The shiftregister used should not be too long, four to eight stages already does a perfect job. Some CMOS shiftregisters can recirculate, which would hold the pattern.

One can expand by having multiple parallel shiftregisters alternatingly clocked on positive and negative flanks of the oscillator pulse and e.g. using the triangles from the oscillators to crossfade between multiple DAs on the multiple shiftregisters, etc. By expanding the number of oscillators and shiftregisters the number of available havoc waves explodes. Basically the rungler is an open ended circuit that can be expanded and chained into multi-rungler networks.

In the current issue of Leonardo Music Journal (issue 19) is an article about the Blippoo Box, the Benjolins Big Brother, and there is more on the rungler circuit in the article as wel as some other thingies I used in the Benjolin as well.

Imho a rungler circuit works best in an analog electronics implementation. It is definitively more alive and surprising due to the slight instabilities in the analog circuitry. I did digital implementations, but they can't beat the 'organic behaviour' of the analog versions. But this is just personal taste..."
Note to self: Order a Hordijk system...
damn right
thanks for posting that richard. it's always interesting to read what rob has to say about things.

Morley wrote:
Note to self: Order a Hordijk system...

that's where half my euro sell off money is going.
should be here around the end of october It's peanut butter jelly time!
rob is an absolute pleasure to deal with.
been lucky enough to pick a single one up.
real great module, very impressive and inspiring thumbs up
congrats sandyb!

yes he's a serious, properly decent and supersmart freak of a guy. just the kind of dude we need making our modulars. I have been lusting for one of his systems since before they existed, but since my solemn vow to never leave the true path of the banana all that remains is to tempt Rob over to my evil ways. I do a little dance every night to weaken his resolve. Goes something like this:

It's peanut butter jelly time! twisted nanners twisted It's peanut butter jelly time! nanners twisted It's peanut butter jelly time! nanners
Thanks for posting this - I have benjolini in the works, and it's always good to have some kind of clue as to what's actually happening in the system.
Very happy with my Rungler.
Sorta like a Noisering but way more advanced and controllable !

Just visited Rob at his workshop to pick up a system... am going to do a post about it in 5U later on in the week when I get back to Manchester and put it through my sound card.

Have to say it was a very inspiring trip... two Runglers battling it out together sounds amazing!!!
Nelson Baboon
Chaos is evil
Order is evil
Nelson Baboon
Therefore chaos is order
is is is evil order chaos is
Om Chaos is the Mother of Cosmos Om

hihi couldn't resist
time to restart the initial conditions of the thread according to principles of Chaos theory hihi

does the Rungler actually exhibit Chaotic behaviour or is it random?

seriously, i just don't get it
Now I want : PLOG + Elby/CGS Shift Register
I actually have no idea how these things are understood formally by mathematicians but in my understanding randomness assumes an arithmetical state of non-repetitiveness, a kind of equality of distribution of non-predictably occurring elements - the most obvious musical examples of which would be an ideal white noise.

Chaos assumes recursive elements (such as feedback) from which repetitive elements are systematically derived. The outcome of such as system is determined by the initial conditions but not strictly predictable from them. Its outcomes may appear random but strictly speaking, they are aren't because they are systematically determined.

If so then the rungler, and the way it connects memory and captures and recycles time is very much the latter.

But I'm sure others here could offer a more exact definition?
"look away Richard, don't look at the beautiful 12 module hordijk suitcase, look away now."

(and repeat)
But is he totally opposed to make stuff utilizing the divine connector* ?

* banana jacks
Well, maybe Rob would weigh in on that question himself? Not sure how often he visits the forum though.

From what I remember of our conversations: the 5U modular stuff has a lot of normalization and is considered from the ground up as a jack format - with the matrix doing all the multing and buffering. So every board would need redesigning with additional buffering, meaning a banana version would involve a huge amount of redesigning and perhaps rethinking too.

Banana Blippoos are available on request and he certainly "gets" the benefit of the different workflow, especially for improvising - which unlike many designers he does really "get". He even somewhat discouraged me from buying a big 5U system I had specced out last year because he knew the form wouldn't really suit me (seriously, how many manufacturers would do that?).

I see Rob as a primarily a fantastic designer, who happens to be also a fantastic manufacturer, who happens to be concentrated on making fantastic 5U systems at the moment. As for what could happen in future... where his focus might go, or what somebody else might do with his designs, well, its already started with the Benjolin... Rob is truly a forward thinker so I don't think the story is over yet!
Here's a little ditty with the blippoo's runglers A and B driving the Z-DSP bat filter. What I love about this device (the blippoo) is that it is totally playable, and you soon develop a good feel for how it's going to behave. It's not at all random, but it is unpredictable in a very useful and musical (ha!) way.

Hi all, this is Rob.

About chaos, basically a chaotic system is a system that is always trying to find a state of balance. But the most important property is that the system can have more than one, and perhaps millions, of possible states of balance. Once in a state of balance it tends to stay there until the system gets disturbed and then there can be a transition period with what appears random behaviour and then get stuck in another state of balance, until disturbed again.

To keep things easy a 'state of balance' is the equivalent to a 'strange attractor', and in a musical system can appear as a repeating sequence or a waveform.

Chaotic systems tend to have certain behaviour, e.g. a new state of balance might be of an integer number times the length of the previous state, also known as a period doubling.

The rungler circuit in the Blippoo behaves like a chaotic system, having both many possible balanced states, period doublings and transition states. But I must say that the analog components have e.g. temperature dependencies and crosstalk that make the Blippoo slightly more random as a digital implementation would be. But for me that is also a bit of the fun of the Blippoo.

I have an interest in chaotic systems for a long time, partly being inspired by a music theory of the Dutch composer Jan Boerman, who some fifty years ago had the idea to define a musical area between a pure sine as the simplest musical entity and pure noise as the most complex entity and explore the space in between these two. Chaotic systems seem to neatly fit in this area.

And yes, one day I might go bananas...

/Rob Hordijk
richard wrote:
"look away Richard, don't look at the beautiful 12 module hordijk suitcase, look away now."

What if I split the difference and looked at the 808?

Anyway, it looks like there is a whole series of videos:

Although I couldn't find a website for the modules... seriously, i just don't get it
website?: that is mere 21st thinking

we are way beyond that now

something wonderful
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