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The Mutant Brain 

 

24.April.2018

 

Mutant Brain user manual v1.00 

PG1 

 

Hexinverter Électronique, 2018 

 

16 output MIDI to trigger, gate, polyphonic cv…and more  

 

Thank you for your interest in/purchase of the Mutant Brain. We would like to thank you for considering a 
place for the Mutant Brain in your modular synthesizer! Simple to use yet incredibly versatile and highly 
accurate, the Mutant Brain can be the nerve center of your modular system. The Mutant Brain is a Eurorack 
modular format product, available as a built module only. 
 
 

BRIDGING THE GAP 

 
Since the early 1980s MIDI has been how most synthesizers, sequencers, drum machines and keyboards 
have talked to each other. Yet both old and new analogue synthesizers still use voltage for control, in the 
form of continuous CV, gates and triggers. The analogue resurgence and the growth of Eurorack has meant 
that CV-equipped synths have increased, rather than decreased, in popularity. At the same time the number 
of devices capable of sequencing MIDI have proliferated - and many of these tend to be on the cheaper side. 
Then, of course, there is the MIDI sequencer that exists in your computer: DAWs like Cubase and Ableton now 
include incredibly sophisticated MIDI sequencers. If you’re a Eurorack user who wishes to incorporate any 
MIDI device in your setup, or if you wish to use your PC and DAW to control your modular, you need a MIDI to 
CV converter. 
 
With the Mutant Drums Hexinverter Électronique has 

long been focused on providing modular users with the 

best, most exciting and versatile modular drums experience

. With six drum modules and a mixer the only 

thing missing from the Mutant Drums was a means of sequencing. We deliberated for years over the 
question: 

should we make a sequencer for our Mutant Drums? 

But this didn’t seem like the right idea, since 

there has been such a resurgence of inexpensive, standalone MIDI drum machines and sequencing units! 
Why re-invent the wheel? Eurorack already provides plenty of great sequencers, but for many users these 
take up too much rack space, are too expensive, or are too fiddly to use for performanc. For users who do 
invest in a modular sequencer, combining them with other sequencers in a live setting can be tricky without 
the ability to sync transport controls. 
 
What’s needed is a reasonably priced, versatile, low-HP module that can effectively bridge the gap between 
MIDI and CV…….enter, the 

Mutant Brain!

 

 

The Mutant Philosophy 

 

This module brings the Mutant Drums line to full maturity. With seven drum modules, a mixer and now 

the Mutant Brain as the link to your MIDI sequencer of choice, the Mutant Drums form a remarkably 

capable and utterly unique modular drum system. 

 

There are already some great clones of vintage gear out there. The Mutant Drums are different. Although 

every Mutant drum module began life as a classic drum topology, each one has been meticulously 

designed from the ground up. We aim to create fully-fledged instruments that can transcend the 

limitations and exploit the capabilities of the modern modular system. 

Summary of Contents for Mutant Brain

Page 1: ...ms Hexinverter Électronique has long been focused on providing modular users with the best most exciting and versatile modular drums experience With six drum modules and a mixer the only thing missing from the Mutant Drums was a means of sequencing We deliberated for years over the question should we make a sequencer for our Mutant Drums But this didn t seem like the right idea since there has bee...

Page 2: ... setting up a modular keyboard patch with note velocity How about four note polyphony What about using your DAW to sequence your modular sending LFOs as well as notes Mutant brain allows you to do all that and more TECHNICAL SPECIFICATIONS Width 8HP Depth 30mm Current draw 50mA 4mA 12V CV output resolution 12bits V oct or V Hz QUICK START Straight out of the box the Mutant Brain outputs are assign...

Page 3: ...is setup is fairly universal The specific notes used for each drum on channel 10 vary widely from device to device We have used the natural notes white notes from C4 middle C on most keyboards to C5 Depending on what device you are using and your needs it may be easiest to simply match your sequencer mappings to these default settings However there are many ways to assign MIDI notes and events to ...

Page 4: ...to the CV outputs change brightness based to indicate the voltage they are receiving The 12 LEDs next to the gate outputs flash when they receive a gate or trigger Button Mutant Brain is highly configurable but all changes must be made over MIDI In fact there is only one button on the module Press and release the button to reset all the outputs This will Clear all held MIDI notes Turn off all gate...

Page 5: ...SysEx file each time you power up The configuration web page is here http mutantbrainsurgery hexinverter net Downloading SysEx The page lets you create a Mutant Brain patch by making selections in a series of drop down lists When you have set it up the way you want it hit the submit button shown below to download your SysEx file Sending a patch to Mutant Brain Use a SYSEX tool such as MIDI OX on W...

Page 6: ... Press Play The two top LEDs on the Mutant Brain should flash quickly for a very short time The whole process takes a fraction of a second unless you are looking at the module as you press the button you re likely to miss it That s it your Mutant Brain surgery is done and ready to use Viewing or editing an existing patch The configuration web page allows you to open an existing patch which you alr...

Page 7: ... to sequence notes but the MIDI standard is partly geared towards keyboard players and the Note Input allows Mutant Brain to take advantage of MIDI s performance oriented features as well as allowing polyphonic sequencing Say you want to play a mono keyboard patch over MIDI If you play notes one at a time this works the synth plays each note we press However what if you press more than one note at...

Page 8: ...ke this Basic trigger mapping For typical drum triggers where you do not need an associated pitch based CV you can tie a gate output to a specific MIDI note In this case we can bypass the Note Inputs entirely You would set up the gates as shown this is how Mutant Brain is setup by default Multiple MIDI channels Mutant Brain allows you to control each of the four CV outputs and associated gates usi...

Page 9: ...in user manual v1 00 PG9 Hexinverter Électronique 2018 To do this you ll need to use a Note Input for each MIDI channel The following image shows how this can be configured this is how the Mutant Brain is configured by default ...

Page 10: ...rain user manual v1 00 PG10 Hexinverter Électronique 2018 QUICK REFERENCE CARD These are included with every module but if you have lost yours you might find it handy to print it out and have near your modular for reference ...

Page 11: ...ty The lowest pitched note takes precedence If multiple notes are held down and the currently playing note is released the next lowest note plays Polyphonic note mapping modes You may have noticed that as well as the three priority modes the Note Inputs also have options for 2 note cycle 3 note cycle 4 note cycle 2 note chord 3 note chord 4 note chord These options are used in the polyphonic chord...

Page 12: ...ge of a CV output the output will plateau at the highest or lowest allowable value You can also use pitch bend directly to control a CV output This is explained later under the heading Other CV Sources Keyboard splits Mutant Brain allows more than one Note Input to be assigned to the same MIDI input channel This allows you to set up keyboard splits In the example shown notes below C3 play a bass l...

Page 13: ...V C4 MIDI 60 3V C5 MIDI 72 4V C6 MIDI 84 5V C7 MIDI 96 6V C8 MIDI 108 7V C9 MIDI 120 8V Notes which lie outside of this range will be transposed up or down by whole octaves to bring them into the playable range If you want out of range notes to be muted rather than transposed into range you can restrict the note range of the Note Input that is playing the CV output If you want to use a different o...

Page 14: ...or example to map a CC to a CV output we need to give the CC number and the MIDI channel BPM to CV mode maps a BPM of 0 255 BPM over the full voltage range The output is updated once per beat so updates are slow at low BPM and rapid changes in BPM will result in a stepping of the CV If the MIDI clock stops this does not reset the CV the button can be used A fixed voltage can be output by selecting...

Page 15: ...t also have an attack envelope which triggers each time a new key is pressed even if you are playing legato only releasing a key after the next is pressed Or it can be used in any patch where you want an envelope to retrigger without a new note Select gate in the Trig setting for gate mode and retrig for retrigger mode For Trigger mode you can select a specific time in milliseconds or just select ...

Page 16: ...ond Mutant Brain can trigger its gate outputs in response to these tick message Most usefully you can specify the rate at which the gate output will fire as a division of the tempo Mutant Brain can output a clock at the following rates 1 32nd note 3 ticks 1 16 note triplet 4 ticks 1 16 note 6 ticks 1 8 note triplet 8 ticks 1 16 dotted note 9 ticks 1 8 note 12 ticks 1 4 note triplet 16 ticks 1 8 do...

Page 17: ...onnection at the time of the upload and configure your SysEx program to place a delay of 100ms or so between each SysEx buffer The upload should complete within a minute or two When the upload is completed the two top LEDs should blink alternately and rapidly You need to remove power and apply it again to boot up Mutant Brain with the new firmware If there is an error during the upload the left to...

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