Rob Hordijk Dual Envelope Generator: Difference between revisions
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[[File:Hordijk de.png|thumb|200px|Panel design for an early Rob Hordijk DUAL ENV]]The '''DUAL ENV''' is a module by [[Rob Hordijk Design|Rob Hordijk]]. It features two paired envelopes with different shapes, ENV A is a four-stage (attack, decay 1, break level, decay 2, release) and ENV B a two-stage (attack, decay). It also features a Sample and Hold function. There have been a few versions with different envelope stages, toggle switches, and modulation possibilities. |
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Contact Rob directly for details about his modules: rhordijk@xs4all.nl. <br> |
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Both envelope generators share the same gate input, meaning that they can not be triggered separately, though in later versions ENV B featured a toggle switch to allow self-cycling. This also features two LEDs to indicate the gate status of each envelope. |
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Triggering threshold is roughly 100mV above ground, and can be triggered by wave forms other than pulses, e.g. triangle waves.<ref name="rh">Rob Hordijk</ref> |
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Rob also has a subforum at the Electro-Music forum site: |
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http://electro-music.com/forum/index.php?f=185 |
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=== ENV A === |
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[[File:Hordijk de fc.png|thumb|200px|A flow chart explaining the functionality of the DUAL ENV]]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.<ref name="rh" /> |
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The CV input for attack is inverted, so increasing the CV level will shorten the attack time while increasing the decay times for decay 1, decay 2, and release. This means that when MIDI velocity is used as a CV a higher velocity will shorten the attack and increase the other decay times.<ref name="rh" /> |
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Most of Rob's module designs use SSM quad VCA chips, possibly the Analog Devices SSM2164 (?) |
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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.<ref name="rh" /> |
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The ADBDR envelope is designed to finish its attack phase before it can be re-triggered. When used for sequencing this allows for complex envelope shapes producing interesting rhythmic effects, but when used for fast keyboard play it might feel a bit strange to play the module with long attack times.<ref name="rh" /> |
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<b>HRM VCO</b><br> |
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The HRM VCO module can morph from waveform to another because it builds up the harmonic content from a sine and cosine waveform. |
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You can morph with CV from sine to triangle. |
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Note that there are no attenuator knobs to set the amount of modulation for the ADBDR envelope CV inputs allowing for direct connection to velocity CV or CC#. However when modulated from other sources they might need extra CV processing to set the modulation levels properly.<ref name="rh" /> |
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=== Gate or Trig Toggle === |
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<b>Dual Phaser </b><br> |
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New versions of the module feature a toggle switch to select between GATE or TRIG modes. When using long pulses or 'gates' as inputs the envelope will pause at the break level while the gate is high, and continue when the gate is low. Toggle mode will simply run through all stages of the function without interruption. <!-- Need to clarify this with testing or Rob. --> |
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Price: 385 Euro.<br> |
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=== ENV B === |
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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. |
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The second envelope generator is intended as a modulation envelope generator to e.g. sweep a filter or control the harmonic wave shaping of an [[Rob Hordijk OSC HRM|OSC HRM]]. The range is from several milliseconds to about a minute.<ref name="rh" /> |
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Earlier versions featured 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. Later versions traded this for a plain inverted output, and instead gave the envelope a second stage (attack), with a pot for control. |
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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. |
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=== Sample & Hold === |
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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. |
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When modulating decay times with control voltages it is good advise to keep the voltage fixed while the envelope is developing. For example 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 decay time modulation input signal (S&H IN) 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 full sampled signal is sent straight to the S&H OUT, so it can be routed to an input of choice on ENV A or use elsewhere, but is attenuated using the ENV B MOD knob before being sent to the ENV B DECAY function.<ref name="rh" /> |
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[[File:RobHordijk-OSCSYNC-DUALENV-TWINPEAK.jpg.jpg|thumb|A Rob Hordijk DUAL ENV filter (centre) in triple-module format with a TWIN PEAK (right) and OSC SYNC (left) - this version features a toggle switch for GATE or TRIG modes, and another for ENV B self-cycling mode.]] |
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=== Normalisations === |
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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. |
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Many of Rob's designs feature internal connections or 'normalisations' between inputs and outputs. These can be broken by inserting jacks into the inputs. When found together in triple-module formation the following normalised connections were made: |
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* TRIPLE LF-VCO - B PULSE > DUAL ENV - GATE IN |
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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. |
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* DUAL ENV - ENV A OUT > TWINPEAK - VCA CV |
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== References == |
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Audio routing is as follows: |
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{{From Mod Wiggler Wiki|Rob Hordijk Designs}} |
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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. |
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{{reflist}} |
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== External links == |
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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. |
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* Rob Hordijk explains the [http://www.youtube.com/watch?v=Knbkv6OxcsE&list=PLAC347DE38ABA9E8D&index=4 Dual Envelope Generator] at the European Electro Music Event 2012, Mallorca, Spain. |
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[[Category:Original Rob Hordijk Design]] |
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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. |
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[[Category:5U modules]] |
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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." |
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<b>Active Matrix</b><br> |
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Price: a little under 500 Euro.<br> |
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The Active Matrix module is buffered and works similar to the EMS Synthi. |
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It comes with mono plugs and some have built-in resistors for -6db or -12db signal reduction. |
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Every point is an insert, and with an insert cable, you can patch whatever you like into that point. |
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<b>Dual Envelope Generator</b> |
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Latest revision as of 02:54, 20 June 2022
The DUAL ENV is a module by Rob Hordijk. It features two paired envelopes with different shapes, ENV A is a four-stage (attack, decay 1, break level, decay 2, release) and ENV B a two-stage (attack, decay). It also features a Sample and Hold function. There have been a few versions with different envelope stages, toggle switches, and modulation possibilities.
Both envelope generators share the same gate input, meaning that they can not be triggered separately, though in later versions ENV B featured a toggle switch to allow self-cycling. This also features two LEDs to indicate the gate status of each envelope.
Triggering threshold is roughly 100mV above ground, and can be triggered by wave forms other than pulses, e.g. triangle waves.[1]
ENV A
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.[1]
The CV input for attack is inverted, so increasing the CV level will shorten the attack time while increasing the decay times for decay 1, decay 2, and release. This means that when MIDI velocity is used as a CV a higher velocity will shorten the attack and increase the other decay times.[1]
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.[1]
The ADBDR envelope is designed to finish its attack phase before it can be re-triggered. When used for sequencing this allows for complex envelope shapes producing interesting rhythmic effects, but when used for fast keyboard play it might feel a bit strange to play the module with long attack times.[1]
Note that there are no attenuator knobs to set the amount of modulation for the ADBDR envelope CV inputs allowing for direct connection to velocity CV or CC#. However when modulated from other sources they might need extra CV processing to set the modulation levels properly.[1]
Gate or Trig Toggle
New versions of the module feature a toggle switch to select between GATE or TRIG modes. When using long pulses or 'gates' as inputs the envelope will pause at the break level while the gate is high, and continue when the gate is low. Toggle mode will simply run through all stages of the function without interruption.
ENV B
The second envelope generator is intended as a modulation envelope generator to e.g. sweep a filter or control the harmonic wave shaping of an OSC HRM. The range is from several milliseconds to about a minute.[1]
Earlier versions featured 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. Later versions traded this for a plain inverted output, and instead gave the envelope a second stage (attack), with a pot for control.
Sample & Hold
When modulating decay times with control voltages it is good advise to keep the voltage fixed while the envelope is developing. For example 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 decay time modulation input signal (S&H IN) 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 full sampled signal is sent straight to the S&H OUT, so it can be routed to an input of choice on ENV A or use elsewhere, but is attenuated using the ENV B MOD knob before being sent to the ENV B DECAY function.[1]
Normalisations
Many of Rob's designs feature internal connections or 'normalisations' between inputs and outputs. These can be broken by inserting jacks into the inputs. When found together in triple-module formation the following normalised connections were made:
- TRIPLE LF-VCO - B PULSE > DUAL ENV - GATE IN
- DUAL ENV - ENV A OUT > TWINPEAK - VCA CV
References
This page uses Creative Commons Licensed content from Mod Wiggler Wiki:Rob Hordijk Designs (View authors).
External links
- Rob Hordijk explains the Dual Envelope Generator at the European Electro Music Event 2012, Mallorca, Spain.