This CU is an attempt to port Rob Hordijk famous Benjolin synth to the 301 platform. At the heart of the Benjolin is the Rungler circuit (which i will release next), a peculiar device made of an 8 stages shift register and a crude digital\analog converter. It is clocked by Oscillator 2 and fed values by Oscillator 1. But both oscillators can then be frequency modulated by the Rungler itself, enabling a plethora of cross\self mod that gives birth to chaotic behaviours and patterns.
In the mixer section you can set levels for various individual outs. The main output is a sort of PWM obtained by comparing the two triangle outs of the vco’s added to the rungler out. It’s the only out passing through a Low Pass Filter.
Keep in mind that in the original VCO’s and VCF are analogue, and the rungler is really primitive (CMOS) digital technology, so this version will never sound as organic as the true one. Nevertheless i find it awesome in its own way
SYNTH Controls:
VCO1 freq: 1v/oct pitch control of oscillator 1
Rung1: how much the rungler modulates the frequency of VCO1
VCO2 freq: 1v/oct pitch control of oscillator 2
Rung2: how much the rungler modulates the frequency of VCO2
cutoff: 1v/oct control for cutoff frequency of the filter on MAIN out
q: resonance control of the filter on MAIN out
Rung F: controls how much the Rungler modulates filter frequency
MIXER Controls:
tri1: level of triangle output of VCO 1
pls1: level of pulse output of VCO 1
tri2: level of triangle output of VCO 2
pls2: level of pulse output of VCO 2
MAIN: level of the main output
cpu: about 30% firmware: 0.4.11 or later requires: accents tips: experiment with slow vco1 and fast vco2 or vice versa. there’s a lot to explore here notes: this isn’t an exact clone of the benjolin and is somehow simplified. the rungler’s shift register of the original benjolin is fed a xor of vco1 pulse and last bit of the shift register, mine is just vco1 pulse. in the original benjolin you have a loop feature with which you can recirculate datas in the register, i will try to implement that in a future update.
credits and thanks:
Thanks to Rob Hordijk for the infinite inspiration and source of knowledge, i strongly suggest you read his synthesis workshop pages if you haven’t. Here some additional infos on the Rungler concept.
The hardest part to grasp for me was how to create the primitive DAC, i’ve been illuminated tho by the euroreakt Rungler block for Reaktor 6 made by the great @trickyflemming which i thank immensely for his huge work (i donated when the original euro reakt series came out, i suggest every reaktor user to check it and donate or buy the new reaktor 6.3 compatible version on the Unfiltered Audio website.
thank you for your kindness! this is all incredibly fun for me because i’m learning a lot of stuff that’s getting me deeper and deeper, closer to low level stuff i always dreamt to understand. still a lot of road to walk but i have no hurry!
in fact it’s:
2x aliasing triangle + 2x homemade comparators to have pulse out without additional vco
8x sample&hold + micro delay
about 20 vca’s or more
3 rational vca’s
a good amount of mixer channels.
the power here lies in the routing capabilities of the 301!
Benjolino +
ok so, i was making some refinement and ended up with a more faithful interpretation of the original benjo, the data input of the rungler is now the XOR of VCO2 pulse and the last bit of the shift register and i added the nice FM bus of the original. Vco2 can modulate Vco1 and viceversa. It still lacks the “loop” function of the original but i’ll work on it!
Instead of an update i thing its better to have two versions, Benjolino and Benjolino + with added features but more cpu hungry.
SYNTH Controls :
VCO1 freq : 1v/oct pitch control of oscillator 1
Rung1 : how much the rungler modulates the frequency of VCO1
Fm1: how much VCO2 modulates the frequency of VCO1
VCO2 freq : 1v/oct pitch control of oscillator 2
Rung2 : how much the rungler modulates the frequency of VCO2
Fm2: how much VCO1 modulates the frequency of VCO2
cutoff : 1v/oct control for cutoff frequency of the filter on MAIN out
q : resonance control of the filter on MAIN out
Rung F : controls how much the Rungler modulates filter frequency
MIXER Controls :
tri1 : level of triangle output of VCO 1
pls1 : level of pulse output of VCO 1
tri2 : level of triangle output of VCO 2
pls2 : level of pulse output of VCO 2
MAIN : level of the main output (“PWM” compare of both vco’s triangle waves)
You linked me into the hordijk synth workshop papers a couple of weeks ago. I in turn have passed that on to others who appreciate the resource. Again, here, your contribution is outstanding. Will download and let loose the bengiolino… many thanks
“frees the soul” perfectly put!
last night me and my loved one had a jam session, she on the theremin me on benjo (the actual module). we got totally lost in the beauty of those two solo instruments. i think we’ll study a minimal performance to bring live on stages it was really lovely
uh, i didn’t try it in a stereo chain, you are right, it comes out only from the left.
of course on a mono chain it doesn’t make sense to talk about left or right.
i suggest:
a)using it only on mono chains as it is not stereo (a true stereo unit would mean having every element doubled hence too much cpu).
b)if you need it in a stereo chain for some reason you might install kels library in which you’ll find PanMix , a unit to mix mono units in a stereo context.
i anyway strongly suggest you use it in a mono chain as it is pretty heavy on the cpu and adding other stereo units besides it can be a bit too much for the processor i’m afraid.
Very cool. I’ll check it out for sure. I literally only just bought an actual eurorack Benjolin this week so I look forward to delving into that first so then I can spot the differences/influences etc on your take of it.
welcome to the benjolin madhouse!
you’ll notice they sound very different both in terms of actual sound (analog vs digital and also the peculiarity of the all-harmonics distortion of the actual benjo filter when resonance is cranked up) and of generated “sequences”.
please let me know what you think of it once you try it
