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[[File:Hordijk-1.jpg|thumb|Rob posing with one of his modular systems. ]]
To order or inquire about his modules, e-mail Rob directly: rhordijk@xs4all.nl. <br>
'''Rob Hordijk Original Design''' are the [[West Coast|"Dutch West Coast"]]<ref name=":2">[https://www.youtube.com/watch?v=uyEwdrLUa28 Episode 205: Rob Hordijk (2017)] Art + Music + Technology Podcast</ref> style [[5U|5U (Moog Unit)]] modules designed and crafted by Rob Hordijk; based in The Hague, Netherlands. Except for the [[Rob Hordijk Benjolin|Benjolin]], the designs are not available for DIY.
Rob also has [http://electro-music.com/forum/index.php?f=185 a subforum at the Electro-Music forum website]


As Rob has never had a product website for his instruments, the source for much of the information about them comes from direct contact via email - cited directly as ''Rob Hordijk'' <ref name="rh" />
== Biography ==
Born in 1958, self described "synthesizer designer and builder,<ref name=":0">Rob Hordijk Presentation & Synth Tutorial // Modular Meets Leeds 2017 https://www.youtube.com/watch?v=GzW6pTzATG4</ref>" Rob Hordijk began learning electronics from around age 12 after developing a fascination with the glowing tubes in stereo amplifiers.<ref name=":2" /><ref>[http://vimeo.com/107453197 The Designer] by Franz Schuier, 2008</ref> When he was 14 his father who had noticed young Rob's interest gave him a subscription to an electronics course, which lead to an examination for a ham radio license.


Trained as a designer and not a musician, Rob came from an arts background, studying as a sculptor and jeweler in the 1970s. He approached electronic music in a similar spirit to abstract painting, inspired by the ambient works of Brian Eno, and Luigi Russolo's Intonarumori instruments; where attempts were made to blur the boundaries between music and art:<ref name=":2" /><blockquote>"In those days I was quite interested in the idea of sound as a material to be sculpted, in the same way you can sculpt wood and metal. [...] You can make mechanical objects that make all sorts of sounds, or you can make electronic objects that make all sorts of sounds. but what I like about the electronic objects is that you don't see what makes the sound. [...] It opens the way to sort of make it a bit mysterious."<ref name=":2" /></blockquote>In the early 1980s as various integrated circuits, micro-controllers, and processors became available to hobbyists, Rob began buying things such as the early Curtis chips and RCA 1802 based [http://www.old-computers.com/museum/computer.asp?st=1&c=908http://www.old-computers.com/museum/computer.asp?st=1&c=908 SuperElf] processor board out of curiosity more than professional ambition.<ref name=":2" /><ref name=":1" /> Later switching to an Apple ][+ and the Mountain Hardware Music System, for which he developed a Forth language version that could do all sorts of stuff with the Mountain cards, like [https://en.wikipedia.org/wiki/Karplus%E2%80%93Strong_string_synthesis KarplusStrong-type] plucked string sounds and pitch shifting.<ref name=":1" /> His first introduction to a [[DSP]] was to the DMX1000 around 1984. In 1986 he switched to Atari ST and an Akai S900.<ref name=":1" /> These days he is a [http://www.soundonsound.com/sos/jul04/articles/nord.htm Clavia Nord Modular G2] aficionado.<ref name=":1">[http://electro-music.com/forum/post-10645.html&highlight=#10645 Hello to you all], electro-music.com forum, 29 March 2004</ref><blockquote>"I am not really a gear freak. But I do believe in mastering synthesis techniques, in making synthesis a second nature, so to be able to fully concentrate on the creative processes."<ref name=":1" /></blockquote>After finishing art school, Rob also completed 11 years of study in Information Technology, learning about design methods and inventory control.<ref name=":2" />
==5U Module Information==
<br>
<b>OSC HRM</b><br>
<i>Price 325 euro</i> <br>
<i>Width: 2U</i><br>
The Harmonic Oscillator module (OSC HRM) is used to create pitched waveforms with
dynamically controlled timbres. Pitch control law is 1V/Oct and the module uses a platinum
element for temperature stabilization of the pitch curve. Maximum frequency range is from
0.5 Hz to 16.000 Hz and the scale is perfectly tuned in the middle six octaves up to a pitch of
4.000 Hz. When playing pitches higher as 4000 Hz the 1V/Oct scale starts to break down, due
to the necessary internal bandlimiting in the harmonic generators.
The module uses a biquad sine/cosine oscillator at its core and through a process of recursion
harmonic series of overtones are generated. There are two recursion paths, one that produces
all harmonics and one that produces only the odd harmonics. By gradually opening the knobs
that control the amount of recursion more and more harmonics are generated. When only the
all harmonics path is used the waveform morphs smoothly from a sinewave to a waveform
that closely resembles and sounds like a sawtooth or an inverted sawtooth. Opening only the
odd harmonics knob will smoothly morph from a sinewave to a squarewave. When opening
both knobs effects like pulse wave modulation are possible. Building up these harmonic series
is under full voltage control and can be modulated from slow LFO speeds to fast audio rates
to create FM timbres. When the waveforms are modulated there is a negligable amount of
detune (less than 1 cent), though when modulating at audio rates an asymmetry in the
modulating waveform can cause detune effects on deep modulations.
There is an additional VCA incorporated in the module. The final output signal can be taken
from a point just before the VCA and at the output of the VCA. This enables the module to be
easily used in a situation where one wants to modulate another module by an audio rate signal
and have the modulation depth under voltage control using e.g. a LFO waveform, an envelope
voltage signal or a play controller that produces a control voltage, while still having the full
output level signal available on the full output to serve different purposes.
The waveforms have an exceptionally warm sound and when dynamically modulated have a
deep spatial and organic character.
With only one OSC HRM and one DUAL ENV module you can already have a voice with
dynamic timbral and volume control that can do e.g. a pretty solid bass line
<br><br>
[[File:Hordijk_osc_fc.gif]]
<br><br>


As well as his own instruments Rob worked on the Nord Modular G2 including contributing many patches to the Nord Modular online community, and wrote a [https://rhordijk.home.xs4all.nl/ comprehensive unofficial manual] of the instrument. He has produced music for environments, buildings, film, and dance performances, but is yet to produce an official release on a label.<ref name=":1" /> As of 2022 Rob has announced his retirement and will no longer be taking orders.<ref>Mod Wiggler forum: [https://modwiggler.com/forum/viewtopic.php?t=70363&start=2600 Hello Hordijk] </ref>[[File:Evening session modular serge hordijk.jpg|alt=A Rob Hordijk Original Design modular synthesizer (left) with other instruments.|thumb|A Rob Hordijk Original Design modular synthesizer (left) with other instruments. ]]
<b>Dual Phaser </b><br>
<i>Price: 385 euro</i><br>
<i>Width: 2U</i><br>
The internal CV voltage scale is 1V/Oct. Each phaser has a reasonably accurate one volt per octave direct control input that can track the keyboard voltage. Normalization is used, routing the V/Oct input signal of phaser1 into phaser2 when the phaser2 V/Oct input is left unplugged. Total control range is about 18 octaves. The Frq knob goes over the top 9 octaves of this range. Through the V/Oct and Modulation inputs you can go deeper, but you get into the LFO range and audible phasing effects would disappear. It is however possible to use the phasing effect on LFO control signals in the 1Hz to 10Hz range by supplying the V/Oct with e.g. a fixed -5V control signal, which can create quite interesting LFO effects on e.g. drones. All inputs and outputs are DC coupled, so CV signals can pass the module equally well as audio signals. Only the internal resonance is AC coupled, so resonance drops off below roughly 10Hz. Additionally each phaser has a modulation input, also at 1V/Oct when the mode is set to sweep. When the mode is set to spread it behaves like the modulation sensitivity is halved, also when it is in half mode where only half of the poles in each phaser are modulated by this input. These inputs are not normalized, in fact if no plug is connected the modulation level knobs receive a fixed voltage so a manual spread value can be set. Audio input is maximum 12V peak/peak before clipping occurs and there is 6dB attenuation from input to output to enable resonance peaks without clipping. Audio routing is as follows: If a jack is connected to input1, and if input2 is unconnected, then the audio will route into both phasers. In this mode you can use the two phaser outputs as a stereo signal. Connecting a jack to input2 will override this internal input1->input2 connection and separate both phasers. If audio is routed into input1 and if input2 is left unconnected, and if a jack is connected into ónly output2, then the two phasers are automatically set to "inverse parallel" mode. Meaning that if both phasers are set to exactly the same knob settings the phaser outputs would be in exact reverse phase and thus result in almost silence. If audio is routed into input1, and if output1 is connected with a short cable to input2, and if output2 is taken as the overall output, the two phasers are in series and thus result in one 16-pole phaser. To summarize: you can use the phasers fully separated, parallel with two (stereo) outputs on one input signal, parallel with mono output but with one phaser in reversed phase before the mixing of the outputs of the phasers take place on output2, or in series. All this is accomplished by the internal switches in the connectors and only depends on which inputs and outputs have a plug."
<br><br>
[[File:Hordijk_dp.gif]]
<br><br>


== Design Philosophy ==
<b>Active Matrix</b><br>
Rob's personal definition of a modular synthesizer is more to do with modulation than modularity; referring to functional modules as 'sections'. Everything is supposed to be able to modulate or effect everything else. All levels within the system are optomised for comparability with one another.<ref name=":2" />
<i>Price: 295 euro</i><br>
<i>Width: 4U</i><br>
The Active Matrix module is a fully buffered eight by eight matrix where any one of eight
input signals can be added to any one of eight outputs. By using ¼-inch tip-ring-sleeve insert
jacks for the matrix nodes (equal to stereo jacks) a whole range of applications become
possible. First the column input signal is buffered and then routed to the tips of the nodes in
that column. The ring signals of the nodes are basically summing inputs and summed to the
final output signals at the ends of the rows. By connecting a stereo jack where the tip and the
ring are connected directly together, a connection with unity gain is made from a column
input to a row output. If the tip-ring connection in the jack goes through a resistor an
additional attenuation can be accomplished. E.g. a 30k resistor will attenuate by 6dB and a
91k resistor by 12dB.
When a stereo audio cable is soldered to a jack plug and on the other side of the cable a
potentiometer is attached the potentiometer will act like a pot on the node, enabling to set the
mix level by the pot. Basically each node is an insert, just like the inserts on a mixing desk.
And can thus be used in the same way. So, using a jack with a pot means to ‘insert’ the pot
into the signal path. This means that you can insert any other outside world device in the
signal path by using an insert cable with a stereo jack on one side and two mono jacks on the
other, provided signal levels match of course (e.g. 5V pp oscillator output signals will
severely overload line level inputs on e.g. a digital effects rack or the guitar input of a
stompbox). One could also connect a resistive sensor like a light dependent resistor (LDR) to
a jack and make the node light sensitive.
Each column also acts like a multiple. When a mono jack is connected into a node it will pick
up the column input signal from the tip. But the ring input is now short circuited to the ground
through the sleeve of the mono jack and will so disable any input from this particular node to
the row output. This will not interfere with any other nodes in the same column or row,
because of the full buffering of both the column inputs and row outputs. So, any node that is
not used to route a signal to a row output can be used as a multiple output. Meaning that the
matrix is also eight multiples with one buffered input and eight buffered outputs on each
multiple.
Matrices with bigger sizes can be built on demand. Input columns come in multiples of eight
and any number of output rows are possible.
<br><br>
[[File:Hordijk_am.gif]]
<br><br>


=== Ergonomics ===
<b>MiniBay</b><br>
Inspired greatly by the ergonomics of his first syntheseizer, an EMS Putney, as much as negatively inspired by an early Doepfer system he owned, Rob's designs always keep the performing musician in mind saying, "the comfort of playing is much, much better in my opinion, with larger systems."<ref name=":2" /> In keeping with this ergonomic priority the input and output jacks in Rob's designs are all at the bottom of the modules keeping them well clear of the knobs.<ref name=":2" /> In response to a question about whether this rigid format becomes limiting Rob responded:<blockquote>"It is often a good idea if you design something to impose a certain limitation upon yourself. Basically the way I design is at first I go wild, and go complex, until I feel that I've hit some good stuff, and then I simplify. And this process of simplification is quite important because maybe I have a design that could have like 14 knobs and 18 connectors, and then by simplifying it back to 8 knobs and 10 connectors with the most important functions that actually tends to add strength to the design."<ref name=":2" /></blockquote>This design philosophy extends behind the face-plates too, where consideration for ease-of-construction is just as important. With few exceptions, all Hordijk modules consist of 8 pots and 10 jacks. These can then be easily built in batches using two underlying PCBs, one for mounting all the interface components, and another for the underlying module functions, connected with flat ribbon cables and all constructed with the same hardware.<ref name=":2" />
<i>Price: 225 euro</i><br>
<i>Width: 2U</i><br>
The MiniBay is a smaller version of the Active Matrix. It has a four input by six output fully
buffered matrix plus two passive multiples with five jacks each. The matrix section works
exactly like the 8x8 Active Matrix.
<br><br>
[[File:Hordijk_mb.gif]]
<br><br>


=== Chaos ===
<b>Dual Envelope Generator</b><br>
Functionality-wise Rob also draws heavy inspiration from chaos theory which he studied in the 80s reminiscing, "in those days it was more about graphic functions and little pictures but I was curious about how to apply them to music." After some disappointing experiments he learned a couple of tricks that produce musical results.<ref name=":2" />
<i>Price: 295 euro</i><br>
<i>Width: 2U</i><br>
The Dual Envelope module (DUAL ENV) is a fully voltage controlled envelope generator
specifically designed to be used with sequenced music. There are two different types of
envelopes available, one is a four stage (attack, decay1, break level, decay2, release) envelope
and the second is a one stage envelope (decay only). Both envelope generators share the same
gate input, meaning that they can not be triggered separately. Triggering treshold is at roughly
100mV above ground and also accepts e.g. triangle waves.
The ADBDR envelope is primarily intended to be used for volume envelopes. When the
decay2 knob on the first envelope generator is fully open the decay2 acts like the sustain that
you find on most of the traditional envelope generators. In this case the break control will act
like the sustain level. There are CV inputs for the attack, decay1, decay2 and release rates.
The CV for the attack is inversed, so increasing the CV level will shorten the attack time
while increasing the decay times for the decay1, decay2 and release. This means that when
e.g. the key velocity voltage is used a higher velocity will shorten the attack and increase the
other decay times. Rate settings can be from really snappy to pretty slow. Care was taken that
you still have good control over the rates when in the snappy range.
The second envelope generator is intended as a modulation envelope generator to e.g. sweep a
filter or control the harmonic waveshaping of an OSC HRM module. It has an extra output
that is controlled by a bipolar mix knob that can invert the envelope shape and also gives
some extra overall ‘sink’ or ‘lift’ when the output level is increased. Rate can be set from a
glitch to about a minute.
When modulating decay times with control voltages it is good advise to keep the voltage fixed
while the envelope is developing. E.g. trying to modulate the decay time with an audio rate
signal does in general not produce sensible results. A S&H is integrated into the module to
sample the decaytime modulation input signal for the second envelope generator on every
new gate trigger. This way the modulation amount will stay fixed until the module is triggered
again by a new gate pulse. The sampled signal is also brought out on a connector, so it can be
routed to a CV input on the first ADBDR envelope generator. Or be used in any other S&H
application.
The ADBDR envelope is designed in a way that is hás to finish its attack phase to reach its
peak level before it can be retriggered. When used for sequencing this allows for complex
envelope shapes that give interesting rhythmic effects, but when used for keyboard play it
might feel a bit strange to play the module with long attack times and fast play.
Note that there are no attenuator knobs to set the amount of modulation for the ADBDR
envelope CV inputs, these inputs are at full sensitivity. They can be connected directly to e.g.
the velocity CV or CC# CV outputs of a MIDItoCV converter, but when modulated from
other sources one might need an extra CV mixer module to set the modulation levels properly
<br><br>
[[File:Hordijk_de_fc.gif]]
<br><br>


Making a strong distinction between chaotic and 'random' behavior, Rob emphasises the way a disturbed chaotic system tends to seek stability, or a number of balanced states called 'strange attractors'; These balanced states can produce patterns, and when the patterns are short enough to be recognised can produce very musical results. He believes using these methods is the best way to breathe a kind of life or personality into electronic instruments.<ref name=":2" />
<b>Phaser Filter</b><br>

<i>Price: 325 euro</i><br>
== Workshops and Lectures ==
<i>Width: 2U</i><br>
Rob has given a handful of workshops and lectures both demonstrating the functionality of his instruments, and explaining the design philosophy behind them. These include:
The Phaser Filter module combines 5 allpass poles with three lowpass poles in one module.

The five allpass poles are configured as a phaser with positive feedback resonance control,
* 2012, [http://basicelectricityberlin.blogspot.com/2015/03/april-10-hordijk-modular-special.html European Electro Music Event], Mallorca, Spain. Recorded by Pedro Trotz - https://www.youtube.com/playlist?list=PLAC347DE38ABA9E8D
creating two resonant peaks when opened. Then a crossfade knob fades between the input and
* 10 April 2015, at Basic Electricity #15, Berlin. Recorded by Matthias Ochs - https://www.youtube.com/watch?v=JtzQQcacR9A&t=1398s
the output of the phaser and this crossfade mix is the input signal into the lowpass filter. At
* 15 November 2015, recorded by [http://www.osc1899.com Chris David] - https://www.youtube.com/watch?v=Os1bysJCjMw&list=PLKw0bc1wG1afu-3VHTOAXvoTQ2ulJ2rSN
the end of the allpass chain before the crossfader is a phaser monitor output. The lowpass
* 3-4 June 2017 at NOVARS Research Centre in Manchester, UK - https://vimeo.com/233841864
section has a cutoff slope of -18dB/Oct and its own resonance control.
* 2017 at Modular Meets Leeds, UK. Recorded by [https://www.youtube.com/c/DivKidVideo DivKid] - https://www.youtube.com/watch?v=GzW6pTzATG4
Both the phaser section and the lowpass section have a 1V/Oct control law. The phaser has
* 2014, at Sines & Squares Festival, Yoga Room, Islington Mill, Salford, UK https://vimeo.com/111131227
one modulation input and if it is not connected the audio input signal is used as the
* 2019, at Rob's Workshop, The Hague. - https://www.youtube.com/watch?v=T6XpHDU67Mw
modulation signal. This allows for dynamic waveshaping of the input signal on the time axis

without detuning to signal.
== Performances ==
The filter section has two modulation inputs, if the first is not connected the filter audio input
While self confessing, "I'm not a performing artist, I'm a synthesizer builder."<ref name=":0" /> Rob has performed a number of times demonstrating his instruments in a more creative context as opposed to purely technical demonstration. These include:
signal is used to modulate the filter cutoff, allowing for even more dynamic waveshaping just

like in the phaser section. If the second modulation input is not used it uses a signal from
* 22 December 2016 at Noodlebar https://www.youtube.com/watch?v=lBGjkpNS0F8
halfway the lowpass poles to self-modulate, thus producing all-harmonic distortion on the
* 2017 at Modular Meets Leeds 2017 https://www.youtube.com/watch?v=nnlqV4kzzvg
resonance peak when the resonance is set fairly high.

When the 1V/Oct input jack for the filter is not used it inherits the signal from the phaser
== Modular Systems ==
section 1V/Oct input jack.
All circuitry is original and follows Rob's own concepts based on over thirty years experience in [[sound synthesis]] and [[electronic design]].<ref name="rh">Rob Hordijk</ref> He has complete control over the whole module building process; Research &Development, [[prototyping]], panel design, cutting, drilling, [[PCB etching]] and populating, final hardware assembly, calibration and testing. All components and every piece of hardware is carefully selected for reliability and comfort in use.<ref>Mod Wiggler forum:[https://www.modwiggler.com/forum/viewtopic.php?t=53265&postdays=0&postorder=asc&start=0 The Hordijk project]</ref> Panels with the signature ''Original Rob Hordijk Design'' are both designed and built by Rob Hordijk in his workshop in The Hague, The Netherlands.<ref name="rh" />
Both phaser and filter can sweep over a range of roughly 18 octaves and can be modulated up

to really high audio rates. In this last case FM-type and ring-modulator-type effects occur, but
Rob's philosophy and concept of a modular system is that each 'function' has its own inputs and outputs and should be patched up with cables, and not specifically that each function should be a separate physical entity. So, a triple panel is more like a 'section', offering specific musical functionality by grouping together a sensible collection of functions.<ref name="rh" /> Within a triple-module there are several internal normalizations on the input and output jacks, but there are very little 'module to module' normalizations in triple panels and no 'triple to triple' normalizations.<ref name="rh" /> Systems were built in a number of different configurations and cases depending on the customers request. A full four triple-module system in a plywood flight case weights about 23 kilograms, the lightweight flightcase reduces this to 16 kilograms.<ref name="rh" />
with much more timbral control than traditional ring-modulators. E.g. when the outputs of two

OSC HRM modules, set to sinewave output and tuned in some interval, are mixed and routed
As everything is hand built there can be minor cosmetic issues like dustmarks anodized into a frontpanel or some lettering slightly out of focus, basically the usual things that are simply unavoidable with handwork. All electronics however are thoroughly tested and burnt in for several days before a system leaves the workshop. Only high quality precision components are used for the electronics and all pots are of the 'conductive plastic' type that will never develop crackles in the sound and easily last ten times as long as the more common carbon pots. Everything is designed to last a musicians lifetime and first time owners have unlimited warranty on parts and repairs.<ref name="rh" />
into the filter just slight amounts of the internal modulation on either the phaser or the filter

will start to produce ‘undertones’ and ‘overtones’ that are sum and difference frequencies of
=== Format and Power ===
the interval. This exemplifies the idea behind the Phaser Filter architecture, to not only take
Rob's modules conform to the [[5U]] [[MU parts|(Moog Unit)]] (222mm / 8.75") standard. Single modules were produced 2U wide, which Rob later refined into a triple-module 6U (325mm / 12.79") wide standard.<ref name="rh" /> A frame holds the modules in a way that it becomes one solid block. A frame can easily be mounted in a DIY cabinet made of just four shelves, it is fixed in a cabinet with a set of woodscrews from within the frame into the side shelves. Frames can be made up to three triples in width (976 mm wide) and basically any number of rows in height (225 mm per row). The most popular frame is two rows of two triples and measures 651 mm in width and 451 mm in height.<ref name="rh" />
material away like a normal filter does but to also produce new material not present in the

input signal and combine the both to create a vast range of possible timbres.
The plywood flightcases have their power entry either on the left side or on the right side of the case. This should be specified when ordering. The lightweight flightcase has its power entry on the front and for this it needs the TriLFO-Matrix6x4-Nodeproc-MIDI-IECinlet triple or the Rungler-Matrix6x4-Nodeproc-MIDI-IECinlet triple. It lacks the +/-15V MiniXLR power outlet that is available on the other MIDI triples. The MiniXLR might be used for future expansions, to power e.g. a Blippoobox or for powering DIY projects. It should be considered just a convenience if ever needed and not a necessity.<ref name="rh" />
<br><br>

[[File:Hordijk_pf_fc.gif]]
While the panels conform to a 5U MU standard the power distribution board uses MOTM-style connectors and modules with the +/-15V MOTM header can be readily connected and used. However MOTM modules use another 44 mm based grid than the 107 mm MU grid used in the triples, so they would leave a small gap. However and more important: the standard MOTM mounting holes are not compatible with the metric frame profiles, so they can not easily be fixed in our frame. In practise this means that in a user built cabinet with a section for a frame and a section for MOTM modules the MOTM modules can be powered from the Meanwell PSU + power distro board, but it is physically not feasible to mount a MOTM module in a frame without drilling extra mounting holes in the MOTM module front panel.<ref name="rh" />
<br><br>

The power supply used is a Meanwell RD-3513 set to +/-15V. It accepts an input voltage between 100VAC to 240VAC, meaning it can be plugged into a wall anywhere in the world. One PSU can safely supply current to four triples, for a bigger system a second PSU is recommended.<ref name="rh" />[[File:Hordijk Modular.jpeg|alt=A Rob Hordijk Original Design Modular System|thumb|A Rob Hordijk Original Design modular system, showing four triple-panels in a complete case.]]

=== Modules ===
Modules came with various combinations of the following single functions, though some smaller functions were combined; for example the PHASER and FREQ SHIFTER have appeared in both dual and combination formats.
* [[Rob Hordijk Triple LF-VCO|TRIPLE LF-VCO]]
* [[Rob Hordijk Dual Envelope Generator|DUAL ENV]]
* [[Rob Hordijk OSC HRM|OSC HRM]]
* OSC SYNC
* [[Rob Hordijk Rungler|RUNGLER]]
* [[Rob Hordijk Triple-Input 24dB Filter|24dB FILTER]]
* [[Rob Hordijk Twinpeak|TWINPEAK]]
* [[Rob Hordijk Active Matrix|Active Matrix / Mini Bay / MINI MATRIX]]
* [[Rob Hordijk Dual Fader|FADER]]
* [[Rob Hordijk Dual Phaser|PHASER]]
* [[Rob Hordijk ShaperPhaser|SHAPER]]
* [[Rob Hordijk Node Processor|NODE PROC / MINI MATRIX]]
* MINI MATRIX

== Other Instruments ==

*[[Rob Hordijk Blippoo Box|Blippoo Box]] "A patch in a box" - Rob<ref name=":2" />
* [[Rob Hordijk Benjolin|Benjolin]], "Bent by design" / "My gift to the DIY community" - Rob<ref name=":2" />

== References ==
{{From Mod Wiggler Wiki|Rob Hordijk Designs}}
{{reflist}}

== External Links ==
* For enquires, [mailto:rhordijk@xs4all.nl e-mail] Rob Hordijk directly
* [https://modwiggler.com/forum/viewtopic.php?t=70363&sid=61d3112e20ba4147879ab59f0b72593e 'Hello Hordijk'] thread on Mod Wiggler forum
* [http://electro-music.com/forum/forum-185.html Rob Hordijk DIY Designs], on Electro-Music forum
* [https://thehordijkmodular.blogspot.com/ The Hordijk Modular Blog] by Benoit Faivre. A fan-made blog about Rob Hordijk instruments
* ''[http://muse.jhu.edu/login?auth=0&type=summary&url=/journals/leonardo_music_journal/v019/19.hordijk.pdf The Blippoo Box: A Chaotic Electronic Music Instrument, Bent by Design]'' by Rob Hordijk, Leonardo Music Journal, Volume 19, 2009, pp.&nbsp;35–43 – requires a login for access
* Rob Hordijk's [http://rhordijk.home.xs4all.nl/ Clavia Nord Modular G2 Workshops and Tutorials]
* [https://www.modwiggler.com/forum/viewtopic.php?t=32700 Rob Hordijk 24dB MultiMode Filter demos], Mod Wiggler forum, Apr. 2011
* [http://vimeo.com/107453197 The Designer] by Franz Schuier, 2008
* [https://electronicmusic.fandom.com/wiki/Rob_Hordijk_Design Rob Hordijk Design] on https://electronicmusic.fandom.com/
=== Pre-built Eurorack Modules ===
* [https://web.archive.org/web/20141019122935/http://www.epochmodular.net/benjolin.html Benjolin], Epoch Modular
* [https://web.archive.org/web/20150724204314/http://www.xn--klangbaukln-zfb.de/Klangbau,K%C3%B6ln,Koeln,Synthesizer,Module,Klangkunst/rob-hordijk/ Benjolin and Twin Peak Filter], KlangbauKöln

[[Category:Original Rob Hordijk Design]]

Latest revision as of 22:04, 29 June 2022

Rob posing with one of his modular systems.

Rob Hordijk Original Design are the "Dutch West Coast"[1] style 5U (Moog Unit) modules designed and crafted by Rob Hordijk; based in The Hague, Netherlands. Except for the Benjolin, the designs are not available for DIY.

As Rob has never had a product website for his instruments, the source for much of the information about them comes from direct contact via email - cited directly as Rob Hordijk [2]

Biography

Born in 1958, self described "synthesizer designer and builder,[3]" Rob Hordijk began learning electronics from around age 12 after developing a fascination with the glowing tubes in stereo amplifiers.[1][4] When he was 14 his father who had noticed young Rob's interest gave him a subscription to an electronics course, which lead to an examination for a ham radio license.

Trained as a designer and not a musician, Rob came from an arts background, studying as a sculptor and jeweler in the 1970s. He approached electronic music in a similar spirit to abstract painting, inspired by the ambient works of Brian Eno, and Luigi Russolo's Intonarumori instruments; where attempts were made to blur the boundaries between music and art:[1]

"In those days I was quite interested in the idea of sound as a material to be sculpted, in the same way you can sculpt wood and metal. [...] You can make mechanical objects that make all sorts of sounds, or you can make electronic objects that make all sorts of sounds. but what I like about the electronic objects is that you don't see what makes the sound. [...] It opens the way to sort of make it a bit mysterious."[1]

In the early 1980s as various integrated circuits, micro-controllers, and processors became available to hobbyists, Rob began buying things such as the early Curtis chips and RCA 1802 based SuperElf processor board out of curiosity more than professional ambition.[1][5] Later switching to an Apple ][+ and the Mountain Hardware Music System, for which he developed a Forth language version that could do all sorts of stuff with the Mountain cards, like KarplusStrong-type plucked string sounds and pitch shifting.[5] His first introduction to a DSP was to the DMX1000 around 1984. In 1986 he switched to Atari ST and an Akai S900.[5] These days he is a Clavia Nord Modular G2 aficionado.[5]

"I am not really a gear freak. But I do believe in mastering synthesis techniques, in making synthesis a second nature, so to be able to fully concentrate on the creative processes."[5]

After finishing art school, Rob also completed 11 years of study in Information Technology, learning about design methods and inventory control.[1] As well as his own instruments Rob worked on the Nord Modular G2 including contributing many patches to the Nord Modular online community, and wrote a comprehensive unofficial manual of the instrument. He has produced music for environments, buildings, film, and dance performances, but is yet to produce an official release on a label.[5] As of 2022 Rob has announced his retirement and will no longer be taking orders.[6]

A Rob Hordijk Original Design modular synthesizer (left) with other instruments.
A Rob Hordijk Original Design modular synthesizer (left) with other instruments.

Design Philosophy

Rob's personal definition of a modular synthesizer is more to do with modulation than modularity; referring to functional modules as 'sections'. Everything is supposed to be able to modulate or effect everything else. All levels within the system are optomised for comparability with one another.[1]

Ergonomics

Inspired greatly by the ergonomics of his first syntheseizer, an EMS Putney, as much as negatively inspired by an early Doepfer system he owned, Rob's designs always keep the performing musician in mind saying, "the comfort of playing is much, much better in my opinion, with larger systems."[1] In keeping with this ergonomic priority the input and output jacks in Rob's designs are all at the bottom of the modules keeping them well clear of the knobs.[1] In response to a question about whether this rigid format becomes limiting Rob responded:

"It is often a good idea if you design something to impose a certain limitation upon yourself. Basically the way I design is at first I go wild, and go complex, until I feel that I've hit some good stuff, and then I simplify. And this process of simplification is quite important because maybe I have a design that could have like 14 knobs and 18 connectors, and then by simplifying it back to 8 knobs and 10 connectors with the most important functions that actually tends to add strength to the design."[1]

This design philosophy extends behind the face-plates too, where consideration for ease-of-construction is just as important. With few exceptions, all Hordijk modules consist of 8 pots and 10 jacks. These can then be easily built in batches using two underlying PCBs, one for mounting all the interface components, and another for the underlying module functions, connected with flat ribbon cables and all constructed with the same hardware.[1]

Chaos

Functionality-wise Rob also draws heavy inspiration from chaos theory which he studied in the 80s reminiscing, "in those days it was more about graphic functions and little pictures but I was curious about how to apply them to music." After some disappointing experiments he learned a couple of tricks that produce musical results.[1]

Making a strong distinction between chaotic and 'random' behavior, Rob emphasises the way a disturbed chaotic system tends to seek stability, or a number of balanced states called 'strange attractors'; These balanced states can produce patterns, and when the patterns are short enough to be recognised can produce very musical results. He believes using these methods is the best way to breathe a kind of life or personality into electronic instruments.[1]

Workshops and Lectures

Rob has given a handful of workshops and lectures both demonstrating the functionality of his instruments, and explaining the design philosophy behind them. These include:

Performances

While self confessing, "I'm not a performing artist, I'm a synthesizer builder."[3] Rob has performed a number of times demonstrating his instruments in a more creative context as opposed to purely technical demonstration. These include:

Modular Systems

All circuitry is original and follows Rob's own concepts based on over thirty years experience in sound synthesis and electronic design.[2] He has complete control over the whole module building process; Research &Development, prototyping, panel design, cutting, drilling, PCB etching and populating, final hardware assembly, calibration and testing. All components and every piece of hardware is carefully selected for reliability and comfort in use.[7] Panels with the signature Original Rob Hordijk Design are both designed and built by Rob Hordijk in his workshop in The Hague, The Netherlands.[2]

Rob's philosophy and concept of a modular system is that each 'function' has its own inputs and outputs and should be patched up with cables, and not specifically that each function should be a separate physical entity. So, a triple panel is more like a 'section', offering specific musical functionality by grouping together a sensible collection of functions.[2] Within a triple-module there are several internal normalizations on the input and output jacks, but there are very little 'module to module' normalizations in triple panels and no 'triple to triple' normalizations.[2] Systems were built in a number of different configurations and cases depending on the customers request. A full four triple-module system in a plywood flight case weights about 23 kilograms, the lightweight flightcase reduces this to 16 kilograms.[2]

As everything is hand built there can be minor cosmetic issues like dustmarks anodized into a frontpanel or some lettering slightly out of focus, basically the usual things that are simply unavoidable with handwork. All electronics however are thoroughly tested and burnt in for several days before a system leaves the workshop. Only high quality precision components are used for the electronics and all pots are of the 'conductive plastic' type that will never develop crackles in the sound and easily last ten times as long as the more common carbon pots. Everything is designed to last a musicians lifetime and first time owners have unlimited warranty on parts and repairs.[2]

Format and Power

Rob's modules conform to the 5U (Moog Unit) (222mm / 8.75") standard. Single modules were produced 2U wide, which Rob later refined into a triple-module 6U (325mm / 12.79") wide standard.[2] A frame holds the modules in a way that it becomes one solid block. A frame can easily be mounted in a DIY cabinet made of just four shelves, it is fixed in a cabinet with a set of woodscrews from within the frame into the side shelves. Frames can be made up to three triples in width (976 mm wide) and basically any number of rows in height (225 mm per row). The most popular frame is two rows of two triples and measures 651 mm in width and 451 mm in height.[2]

The plywood flightcases have their power entry either on the left side or on the right side of the case. This should be specified when ordering. The lightweight flightcase has its power entry on the front and for this it needs the TriLFO-Matrix6x4-Nodeproc-MIDI-IECinlet triple or the Rungler-Matrix6x4-Nodeproc-MIDI-IECinlet triple. It lacks the +/-15V MiniXLR power outlet that is available on the other MIDI triples. The MiniXLR might be used for future expansions, to power e.g. a Blippoobox or for powering DIY projects. It should be considered just a convenience if ever needed and not a necessity.[2]

While the panels conform to a 5U MU standard the power distribution board uses MOTM-style connectors and modules with the +/-15V MOTM header can be readily connected and used. However MOTM modules use another 44 mm based grid than the 107 mm MU grid used in the triples, so they would leave a small gap. However and more important: the standard MOTM mounting holes are not compatible with the metric frame profiles, so they can not easily be fixed in our frame. In practise this means that in a user built cabinet with a section for a frame and a section for MOTM modules the MOTM modules can be powered from the Meanwell PSU + power distro board, but it is physically not feasible to mount a MOTM module in a frame without drilling extra mounting holes in the MOTM module front panel.[2]

The power supply used is a Meanwell RD-3513 set to +/-15V. It accepts an input voltage between 100VAC to 240VAC, meaning it can be plugged into a wall anywhere in the world. One PSU can safely supply current to four triples, for a bigger system a second PSU is recommended.[2]

A Rob Hordijk Original Design Modular System
A Rob Hordijk Original Design modular system, showing four triple-panels in a complete case.

Modules

Modules came with various combinations of the following single functions, though some smaller functions were combined; for example the PHASER and FREQ SHIFTER have appeared in both dual and combination formats.

Other Instruments

References

This page uses Creative Commons Licensed content from Mod Wiggler Wiki:Rob Hordijk Designs (View authors).

  1. ^ a b c d e f g h i j k l m n o Episode 205: Rob Hordijk (2017) Art + Music + Technology Podcast
  2. ^ a b c d e f g h i j k l Rob Hordijk
  3. ^ a b Rob Hordijk Presentation & Synth Tutorial // Modular Meets Leeds 2017 https://www.youtube.com/watch?v=GzW6pTzATG4
  4. ^ The Designer by Franz Schuier, 2008
  5. ^ a b c d e f Hello to you all, electro-music.com forum, 29 March 2004
  6. ^ Mod Wiggler forum: Hello Hordijk
  7. ^ Mod Wiggler forum:The Hordijk project

External Links

Pre-built Eurorack Modules

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