Hexinverter Mutant Brain
Format: Eurorack
Width: 8HP
Depth: 30mm
Current: 50mA @ + 12V, 4mA @ -12V
Format: Eurorack
Width: 8HP
Depth: 30mm
Current: 50mA @ + 12V, 4mA @ -12V
Mutant Brain is a simple, versatile and sophisticated 16 output MIDI to CV converter. Unlike MIDI to CV devices that use MIDI learn technology to program ports, Mutant Brain is a simpleWeb utilityConfigure the device by loading a SysEx file that can be created by simply entering
Designed with live and studio performances in mind, Mutant Brain eliminates wasted panel space, complicated menu diving, and accidental changes to settings once the device is set up.Simply turn it on and load the SysEx file and it will remember your settings until you change them.
All 16 outputs on the front panel are configurable for many different functions, and you can freely assign 4 CV outputs and 12 Gate/Trig outputs, each with different MIDI channels and note ranges.
The table below shows the Mutant Brain factory output configuration.
The preloaded patches are each4 pairs of CV and Gate set to their own MIDI channel,in addition8 Trigger outputs set to individual MIDI channelsis configured toMany MIDI sequencers use channels 1 and 2 for their default MIDI note output, and many drum machines use channel 10, so this setup is reasonably universal.
The specific notes used for each drum on channel 10 depend on the equipment you use.In this setting, most keyboards use the middle 'C', C4 through C5.Depending on your equipment and goals, it may be easier to simply match your sequencer's mappings to these default settings.
However, there are many ways to assign MIDI notes and events to these outputs, as shown in the illustration below.
The front panel of the Mutant Brain has the following connection sockets:
Details of the 18 LED indicators.
A single button press on the interface resets all outputs and does the following:
This button also has special uses during power up when uploading new firmware.
Mutant Brain allows you to use a web page to set configuration parameters and download MIDI SysEx files to save to your computer.This file can be sent to the Mutant Brain to set up new configurations and store the file for later use (you can create different configuration files for the Mutant Brain and build a library of SysEx files). increase).
Mutant Brain remembers the last patch when it was powered down, so you don't have to load the SysEx file every time you power up.
Here is the configuration web page used to create the SysEx file: http://mutantbrainsurgery.hexinverter.net/
The configuration page lets you create Mutant Brain patches by selecting from a series of drop-down lists.Once you have your preferences set, download the SysEx file by clicking the button in the image below.
SYSEX toolsusing (in WinMIDI-OX, on MacSys Ex Librarianetc.) Send this file to your Mutant Brain.
The web configuration page allows you to open an existing patch saved as a SysEx file.To do so, select a file to upload using the button at the top of the web page.
The basic level of the configuration page consists of the following sections.
One thing to note about the 'Note Inputs' dropdown on the Mutant Brain Surgery page is that notes (except drum triggers) can only be mapped to CV outputs via 'Note Input'.You can't simply map MIDI notes to CV outputs.
Many modular users don't use keyboards to sequence notes, but the MIDI standard is aimed in part at keyboard players, and with Note Input Mutant Brain takes advantage of MIDI's performance-oriented capabilities. , a polyphonic sequence can be realized.
For example, let's say you want to play a mono keyboard patch over MIDI. If we play notes one by one, the synthesizer will play each note we press.But what if you press multiple notes at the same time? A monophonic synthesizer played over MIDI must decide to play only one of the notes it holds.And when you release that note, it may start playing one of the other notes you hold down at the same time (depending on which synthesizer you're using).Such "prioritization" is a useful feature for keyboard players and can be used to play nice trills or alternating lead and bass notes.
The Mutant Brain has to make the same decisions, so it has to "listen" for MIDI notes and decide which ones to send for mapping to the CV output.This is why you need "Note Inputs". Note Inputs prioritize notes and determine which notes should be mapped to the CV output.For polyphonic mode, Note Input must be set separately from the CV outputs themselves, as notes may be played on more than one CV output.
Suppose we want to control a mono patch with MIDI notes on MIDI channel 1. When using a MIDI sequencer, it doesn't matter how the note priorities are set, because you never play two notes at the same time.
If you want to accept any note at any velocity, send pitch to CV output A, and gate to Gate output 1, you'll need two mappings:
To perform these, set up the Mutant Brain Surgery form as follows
A typical drum trigger doesn't need a pitch-based CV, so you can tie the gate output to a specific MIDI note.In this case, you can bypass Note Inputs completely.
Set the gate as shown below (this is the default setting for Mutant Brain).
For a typical drum trigger, you don't need a CV based on pitch, so you can tie the gate output to a specific MIDI note.In this case, you can bypass Note Inputs completely.Set the gate as shown below (this is the default setting for Mutant Brain).
Mutant Brain allows you to control each of the 4 CV outputs (and associated gates) using a different MIDI channel.This allows you to run 1 sequencers on each channel from a single device that supports multiple MIDI channels, or from multiple devices with Mutant Brain daisy-chained at the end.
To do this, we need to use a Note Input for each MIDI channel.The following image shows how this is set up (default for Mutant Brain).
The sections that follow will go into more detail on all the Gate, Trigger, and CV options, as well as the MIDI to CV implementation.
Each Note input has 3 note priority modes, used for monophonic assignments.These are not important when using a sequencer, but are very useful for keyboard players.
Besides the three priority modes, Note inputs have the following options:
These options are used in polyphonic 'chord' and 'cycle' modes, allowing one note input to control up to 1 CV and 4 Gate outputs.
Here's an example of mapping 4 CV/Gate output pairs to play 4 chords across 4 voices.
MIDI pitch bend is automatically applied to notes mapped via Note Input.A configuration web page can be used to specify the pitch bend range to use for a particular note entry.For example, if applying pitch bend puts a note outside the range of the CV output, the output will be capped at the maximum or minimum value allowed.You can also use pitch bend directly to control the CV output.This is covered in the "Other CV Sources" section below.
Mutant Brain can assign multiple Note Inputs to the same MIDI input channel.This allows you to set keyboard splits.In the setup in the image below, notes below C3 play the bassline on the first oscillator, notes above play the lead synth line on the second oscillator, and both synths are at the highest pitch. It will be played with note priority.
When the Mutant Brain sends a musical pitch CV, it uses a 1V/Oct reference, 8 octave range signal.Middle C (MIDI note: 60) is set to 3 volts, so the output range is approximately MIDI note 24 (C1) to 120 (C9).
Notes outside this range are transposed one octave up or down into a playable range.
If you want to mute out-of-range notes (rather than transpose them in-range), you can limit the range of the Note input playing the CV output.
If you want to use a different octave mapping, you can use Note Input's transpose function.For example, if you want to map MIDI note 0 (C-1) to 0 volts, set the CV's 'Transpose' to +2 octaves.
Notes beyond the playable range due to pitch bend are limited by their limits.
Mutant Brain's 4 analog CV outputs can output the following signals in addition to musical pitch CV.
Each of these can specify a full CV voltage range from 1V to 8V.Additional parameters required for mapping are listed above.For example, to map CC to CV output, you need to specify the CC number and MIDI channel.
BPM to CV mode maps 0-255bpm BPM over the entire voltage range.The output is updated once per beat, so slow BPM updates are slow and rapid changes in BPM will result in 'stepping' of the CV. If the MIDI clock stops, the CV will not be reset (buttons are still available).
You can output a fixed voltage by selecting the required voltage in the 'Range' dropdown.This constant voltage output is useful for module calibration.
Mutant Brain features 12 assignable Gate outputs.Each of these outputs can be turned ON/OFF according to incoming information from MIDI.
Depending on how the Gate output is mapped, it will toggle on and off when the corresponding event occurs on the MIDI input. Three modes are available.
Gate mode selects ' gate ' in Trig setting and ' retrig ' in retrig mode.For trigger mode, select a specific time in milliseconds or 'trigger' to use the default trigger period defined in the global settings.
The trigger period in the global setting applies only to trigger mode.The 'low' time in retrigger mode is very short (~1ms), long enough to give a rising edge to trigger the synthesizer.
MIDI has the concept of a "play" mode (or "transport").When the transport is running, this means pattern-based devices and sequencers play notes in sync with MIDI clock.The transport can also be stopped. MIDI controls playback with three messages:
Mutant Brain has a handy feature that outputs a clock pulse when it receives a MIDI clock tick message. The MIDI clock master sends 4 tick messages per "beat" (quarter note) to define the BPM, so at 24bpm you will receive 120 ticks per second. The Mutant Brain can trigger gate outputs in response to these tick messages.
Mutant Brain can specify the period to output the gate by dividing the tempo, and can output the clock with the following period.
The gate output can be tied to a specific MIDI CC value so that the gate activates when the CC value is above or below the threshold.For example, you can set the gate to fire when CC#10 exceeds the value 64.
You can also set the gate to trigger when CC goes below the threshold.In either case, the gate cannot be triggered until it receives the current CC value from MIDI (when using Mutant Brain for the first time, the current CC value is unknown until you change it).