Rungler ideas
  • @stschoen Re. the using the anti-aliased oscillator nodes – when I started piecing the Blippoo together I at first thought that given the ‘noisy’ context the phasor based oscillators would be fine, but then changed to the oscillator nodes since I figured that given the chaotic/noisy behavior of the circuit that it would be good to have as clean a starting point as possible, and that was an easy change since there aren’t really any alingment considerations with the Blippoo. I think it does make a difference.

    One could also argue that the Rungler idea (see the Leeds video above at 1m15s) is to span the continuum from pure tone to complete noise – I think it could be interesting to try out an anti-aliased version and compare the difference in this digital context.
  • @stschoen Two things I noticed with the Rungler patch:

    - The rungler amount for oscillator A only adds an alternation between two tones, whereas with oscillator B it works as expected.
    - The Density amount only affects the pulse output.

    I was also thinking that the density switch could be implemented in a way similar to Pugix’s frequency range in the Quantussy: http://forum.audulus.com/discussion/1244#Item_6

    I already started playing around with a compact version of the UI, but perhaps it makes more sense to wait until all the details are ironed out.
  • I noticed the same thing with the rungler on A. I believe it's related to the the fact that A is the clock source for the shift register. When A is in the audio range, so is the shift register. If B is much slower than A, what is feed into the shift register by B will be primarily a long series of ones followed by a long series of zeros so you will get something close to a square wave out of the rungler rather than series of steps. The density knob was an attempt to replicate the sparse/dense/always switch. It changes the probability that the pulse output will change state. Since the pulse output is fed back into A, changing the knob will affect how often the pattern from the rungler changes.
  • @stschoen That’s a good explanation – the only thing is that even when B is up in (a similar) audio range the rungler modulation on A seems a lot less noisy than when swopping the frequencies around and turning up the rungle modulation on B.

    Also if you look at around 8m44s in the Mallorca video he has B turned quite low and still gets a strong S&H type effect when turning up the rungler modulation for A. (By the way I shifted the rungler knobs to just below the osc. rate knobs in my version – just to make it easier to follow what’s going on in the video.)

    Also, I was looking at the internals of patch and could see that the pulse is fed back into A and changing the knob should change the rungler pattern, but I simply can't notice any difference when listening to the triangle or sine outputs.
  • Remember that A clocks the rungler and B provides the data so their behavior will be different. Since I don't have a schematic available, I'm guessing at some of the details and I probably haven't matched the original circuitry, also we have a z-1 node that delays the feedback slightly compared to the original and even small variations in a chaotic system can lead to large changes in the output. BTW if the density control is all the way up or down the pulse will be locked high or low, and the pulse output to A will be a constant value. Try slowing down A into LFO range and controlling and oscillator with the step output. You will find that changing the density will affect how often the rungler pattern changes. You should also see changes in the pattern when you increase the A modulation
  • The modified shift register seems to be working and no longer loses its pattern at high frequencies. Here's the new version of the Rungler. I also posted a new version of the Benjolin in its thread.

    updated version posted below
  • Great! BTW I noticed at the end of Hordijk’s Rungler Demo at Modular Meets Leeds (at around 14min) that he actually has the Rungler (stepped) out set to cover a range of 9 octaves.
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  • If you're talking about using the step output to drive an external oscillator, I scaled the step out between 0 and 1 to stay in line with the general guidelines for modulation values but as @RobertSyrett points out, that's easy to fix.. Here's a little scale and offset uModule. It's currently configured to scale to 4 octaves and offset +- 2 octaves. You can easily change the range by adjusting the equations. If you are talking about using the step output as an audio signal directly, I believe that I configured the A and B oscillator for a range of 14 octaves, from 0 to 16k. Depending on the pattern, the step output would scale over about 7. You could increase the upper frequency limit of the A and B oscillators, but I wanted to make the low frequency adjustment as wide as possible.
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  • Don’t forget that the step output is unipolar. If you’re using it as audio you may want to include a dc blocker.
  • I noticed in James Cigler’s Benjolin video tutorial that the rungler signal is actually bipolar (around 6m30s): https://youtu.be/KCjREVFc6iA?t=6m30s
  • @stschoen Re. the oscillator range: On the electro-music forum he mentions the Benjolin oscillators covering a range of 18 octaves – which I guess would make sense with the 9 steps. http://www.electro-music.com/forum/topic-38081.html
  • @Rudiger, you're correct that the Rungler output on the original unit is bi-polar. In addition to the video you posted, It's shown very clearly at about 17m in Rob's masterclass on noise generation
    Good catch, I hadn't noticed this before. Since the rungler output on my copy varies between 0 and 1, you could get get the same effect by subtracting 0.5 from the signal and multiplying by 2 to get a -1 to 1 output. With respect to the Audulus clone I guess the question is whether the Rungler output is a modulation signal or audio signal. Since we have a de-facto standard of 0-1 for modulation signals and I think that is the more likely use of the Rungler output I think it would be best to leave it as is, and scale and offset it as needed for audio use.

    As far as the oscillator range is concerned, I realized this morning that when I mentioned 14 octaves for my copy, I had taken 2Hz as the lower bound. The real bottom limit for the oscillators is 0.001 Hz, so the actual range is approximately 25 octaves, although I'm not sure that this has much meaning when applied to something running at sub-audio rates. I choose 2^14 as the upper limit for the oscillators since that's slightly above 16K and that seemed high enough. 2^15 would have been 32K which is well above the Nyquist limit and so couldn't be produced in any case at a 44.1k sample rate.
  • I modified the range of the internal Rungler signal to -1 to 1 to be more in line with the original. The module output is still 0-1.

    02:30 PM changed range on Rungler fluctuation modulation back to 1 to 0. Since the unmodulated oscillator output amplitude is already -1 to 1 peak to peak, I would have to reduce the unmodulated output in order to accommodate a bipolar "fluctuation" since the amplitude would have to increase for some Rungler steps.
    STS Rungler V6.1.audulus
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  • @stschoen I’d forgotten about the Noise Generators masterclass – It’s been a while since I looked at it – I should go back and take a look again. A lot of great material.

    Re. the oscillators – yes, I guess it makes sense with analogue gear to be able to go beyond the range of hearing when one can still get ring modulation effects and so on, but of course with Audulus (or the digital realm in general) there are other considerations. Thanks for the run through on your reasoning.

    Thanks for the Rungler updates – so much to consider!
    I’ve taken the liberty of adding the tanh() rounding to the triangle fluctuation and sine out on VCO A – i.e. VCO A sine out is actually the triangle out rounded to give the parabol waveform. I think it adds a lot to the Fluctuation modulation.
    STS Rungler V6.1 Fluct.audulus
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  • This has very much turned into the big Rungler thread, but since it was here I started with my Putney Blippoo experiments I’ll continue here too:

    Here’s the current state of my Blippoo – now all collected in a box. I’m not sure if I’m quite happy with it yet. There were many things that I enjoyed in previous versions that I miss a little here. Having access to more of the TwinPeak filter for example. I’ve kept to the classic 12 knob setup for a start – perhaps I can play around with some alternatives later. The rungler core is now in it‘s perhaps most simple form – a simple kind of delay with no density or looping settings as in the Benjolin or Rungler Module. One of the tricky things is keep it from getting stuck for long periods of time. This happens especially when VCO A is running at a much slower rate than VCO B – and it’s in those situations that the S&H to Rate A is a handy dial to have.

    I’m also not sure about all the internal sub patches. They’ve been a very useful way of building it up, and even now when I’m still unsure about a lot of things and still thinking about possible changes, it’s handy to have it set up that way. But perhaps once it’s all figured out it could be worthwhile going back and rebuilding the patch with fewer submodules and a little less spaghetti.

    There are also still moments when it starts to break up, despite the inclusion of the z-1 nodes at the feedback points, so there might still be some work to be done there.

    RH Blippoo New Shift RM.audulus
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  • Played around with the Blippoo a little this evening, and feeling happier with it than I was yesterday. Here it is with a dual version of STS’ all pass reverb.
    RH Blippoo New Shift Reverb RM.audulus
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  • Sounds almost like it's playing a fanfare!
  • @rudiger this new one sounds like a choir played in FF through a tape machine lol LOVE IT!
  • @stsschoen Another detail I noticed about the Rungler ouputs – in the Mallorca video at around 9m32s he feeds the pulse output into another oscillator – and it seems as if this too is set to cover a range of 9 octaves (in the video, as far as I can tell, he attenuates the signal to about 4 octaves).

    I did a little tryout with your Rungler and it seems as if it helps in creating a more ‘noisy’ noise (for want of a better way of describing it) when bringing the pulses up into audio range.
    STS Rungler V6.1 Pulse RM.audulus
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  • I really like the latest version of your Blippoo implementation. It's definitely coming together. I found Hordijk's designs to be a lot of fun to play with and I'm really glad you started this thread and introduced me to his work.

    Even though it doesn't strictly match the original, I decided to keep the pulse and step outputs of my versions of the Rungler and Benjolin modules between 0 and 1 in order to stay consistent with the usual range for modulation signals in Audulus. Although both outputs can certainly be used for any purpose, I believe that they will mostly be used as modulation of various sorts. I personally agree with @biminiroad that standard ranges for the various signal types within Audulus help us more easily share each other's work. Depending on the user’s needs, the range and centerpoint of a 0 to 1 signal can easily be scaled to whatever is required. I think it's also best to keep audio signals within the -1 to 1 range since Audulus will clip to this level at output and many modules assume that audio levels don't exceed these limits. That being said, I did check on the original specs, at least for the eurorack version of the Benjolin, and the voltage ranges are as follows:
    OUTPUTS:
    Pulse A and B: Average -/+ 8V or 16V P/P. Triangle A and B: Average -/+ 4.5V or 9V P/P.
    XOR: Logic output from rungler. Averages -/+ 5.5V or 11V P/P.
    Rungler: Averages -/+ 5.5V or 11V P/P. PWM: Averages -/+ 8V or 16V P/P.
    Filter Outs: Filter outputs are around line level (approx. -/+ 1.5V or 3V P/P)

    I think it's interesting that all of the signals are bi-polar. At 1 volt per octave, the pulse output could potentially cover 16 octaves! Of course with hardware it's always easier to attenuate a strong signal than boost a weak one, so it would make sense to output the largest practical signal given your hardware and supply voltage. Since Eurorack equipment has a +/- 12 volt supply, it's reasonable to assume that signals will fall somewhere within that range.
  • Thanks for the encouraging words. And thanks for the Eurorack specs.

    I agree with your reasoning that in the Audulus it makes sense to keep to the 1/o standard so that modules can easily be shared and combined. Hordijk has his own, more or less complete modular system, and there are other considerations that make sense in that context, also with regard to attenuating a strong hardware signal rather than boosting a weak one – as you point out.

    I find it interesting that the wide-range signals lead to different sound results – especially with the character of the noise in the Rungler. (I guess it makes sense for ‘noise’ to span as wide a range as possible.) I’d gotten so used to the 1/o standard that I hadn’t even considered it as a possibility.
    It’s good to have these considerations thought through. And as RobertSyrett points out, it’s very easy to convert the signals on the fly in Audulus. (Also I think it’s Robert that deserves much of the credit for his contribution to these Hordijk threads :-)

    Regarding the signals, I kept the S&H out in the Blippoo as a unipolar 1/o signal whereas the internal S&H to VCO A remains bipolar. I also tried out jamming the outputs right under the knobs since that way I could easily experiment with shifting the layout around a bit, and extra labels for the outputs are no longer needed. That makes the outputs a little more difficult to get at, but it’s still possible if one aims for the bottom of the circle. I very much like the uModular form, but sometimes it’s nice to have a little more space at ones disposal for knob labels. The Blippoo and Benjolin also make sense as standalone modules to some degree. I’m keen to tryout a micro version too though.
  • OK, here’s a bit of a find – while doing some searches on the Synthi 100 I came across this post on some performances by Peter Beyls in the 70s that seem to pretty much match the setup Ron Hordijk was describing as the inspiration for his Blippoo/Benjolin/Rungler:
    “Interesting are the use of two EMS VCS3’s, communicating through a very long tape-delay-loop” —http://wp.thesynthi.de/2012/03/22/peter-beyls-1974/

    And there’s some nice film footage of it too!
    https://youtu.be/btpYLJzWuO4
  • Here's a reworking of the STS Rungler with a few internal adjustments, most importantly the way the density switch was working. It now selects how much of the Rungler signal gets fed back into the shift register and gives a better result. It seems to be in line with what Hordijk describes and demonstrates in the NOVARS tutorial video: https://vimeo.com/channels/1311476/237385725

    I also made some adjustments to the layout, with the idea of clarifying the internal routing. The sine and triangle, as well as stepped, smoothed, and pulsed outputs are now placed directly underneath their respective modulation knobs. (Some of them have been doubled for the sake of (visual) consistency.) The density switch changes from ‘random’ in the upper position (the full rungler signal), to ‘sparse’ in the middle (1/3rd of the signal) and ‘dense’ (2/3rds of the signal) in the lower position.

    I've kept the 9 octave pulse output, thinking that it can always be attenuated and offset, and be useful in conjunction with other oscillators. The regular unipolar and bipolar versions of the signal are also available.

    Edit: The sine output on oscillator A somehow got disconnected in both patches – now fixed and re-uploaded.
    RH-STS-RM Rungler 6.2r.audulus
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    RH-RM Rungler Waveform Demo.audulus
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