Max gen~

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Apart from programming LV2-plugins in a "traditional" way, it's also possible to generate LV2-plugins for MOD devices from gen~ objects created in Cycling '74 Max.
This page will tell you the how and why of programming audio effects for the MOD Duo using this very different approach.

Gen basics

Gen~ objects are normally used in Max as a way to write low-level code that is run at signal-rate, using (if you want to) the same visual approach Max is known for.
Therefore the insides of a gen~ object can be seen as a pedal schematic, perfect for designing audio effects.
The SHIRO plugins are an example of plugins for MOD devices made using this very method.

If you're not familiar with Gen, and this sounds all like gibberish to you, have a look at the links below.

Designing your effect in Gen

If you want to design a plugin for a MOD device, there are a few things you should know:

  • To get your gen~ object working on a MOD device, you'll need to design one using only Gen's internal objects, without referring to objects outside the gen~ object.
    Only the objects inside will make it to the final LV2-plugin.
  • If you want controllable parameters, define the default, minimum and maximum arguments in the "param" object.
  • While designing your gen~ object, remember that all MOD devices are running at 48 kHz sampling rate.

You'll find some example-plugins if you download the MOD Duo-package from the Package Manager in Max, and click on Launch.

Getting your Gen-based plugin to a MOD device

At this point you should have met the requirements specified above. If so, follow the steps below to get your plugin on a MOD device.
In order to run Gen-based plugins on a MOD device they must be converted into LV2 plugins and compiled using a custom MOD cloud build system.
All the heavy work has already been done by the MOD Team and Cycling '74.

  • Go to or install the MOD Duo-package in the Package Manager in Max if you haven't, and click on Launch.
  • Make sure your MOD device is connected, then start the MODwatcher from the popped-up screen.
  • If you want your plugin to have a name, copy your gen~ objects contents to a gen~ object with a patcher-name argument.
    WARNING: naming your original gen~ object will initialize it's contents.
  • Finally send a message containing "exportnotifier MODwatcher, exportcode" (without the quotation marks) to the gen~ object.

Your plugin will now be transferred to the MOD device, within a few minutes the MODwatcher will tell you if the upload succeeded.
If all goes well, your Gen-based plugin should now be inside the MOD device, ready to be played!

Additional features (advanced)

Optionally you can edit your plugin to, for example, add units, knob behavior, a description or even a GUI.

Your Gen-based plugin will only show knobs for each parameter. To get switches, selector, etc.. you’ll have to edit the .ttl file and add/change a few lines.

If you get knobs named like your data Gen~ object in Max, you can just ignore those parameters.
 These extra parameters are a side effect from how max gen works, if they really bother you, edit the main plugin .ttl file and set those as OutputPort instead of InputPort.

On a Mac you can do this with the nano editor:

Video tuto here :

  • Open up Terminal
  • Enter
$ ssh root@
  • Password
$ mod
  • Enter

i.e. to get a switch for this parameter:

a lv2:InputPort ,

        lv2:ControlPort ;
       lv2:index 5 ;
       lv2:symbol “FILTER” ;
       lv2:name “FILTER” ;
       lv2:default 0 ;
       lv2:minimum 0 ;
       lv2:maximum 1 ;
  • Add this line : lv2:portProperty lv2:integer, lv2:toggled  ;

which gives:

a lv2:InputPort ,

        lv2:ControlPort ;
       lv2:index 5 ;
       lv2:symbol “FILTER” ;
       lv2:name “FILTER” ;
       lv2:default 0 ;
       lv2:minimum 0 ;
       lv2:maximum 1 ;
       lv2:portProperty lv2:integer, lv2:toggled  ;

i.e if you want the host/mod tempo to control a time parameter

  • Add this line to the prefix list (at the beginning of the file):

@prefix  time: <> .

  • and these lines to the time Control Port which will give:

lv2:ControlPort ;

       lv2:index 2 ;
       lv2:symbol "BPM" ;
       lv2:name "BPM" ;
       lv2:default 120 ;
       lv2:minimum 24 ;
       lv2:maximum 280 ;
       units:unit units:bpm ;
       lv2:portProperty  mod:tempoRelatedDynamicScalePoints;

i.e if you want a selector

  • Add this line to the prefix list (at the beginning of the file):

@prefix rdf: <> .

And change i.e. this:

a lv2:InputPort, lv2:ControlPort ;
       lv2:index 6 ;
       lv2:name "Div_L" ;
       lv2:symbol "Div_L" ;
       lv2:default 1.000000 ;
       lv2:minimum 1.000000 ;
       lv2:maximum 5.000000 ;

To this :

a lv2:InputPort, lv2:ControlPort ;
       lv2:index 6 ;
       lv2:name "Div" ;
       lv2:symbol "Div" ;
       lv2:default 1.0 ;
       lv2:minimum 1.0 ;
       lv2:maximum 5.0 ;
       lv2:portProperty lv2:integer;
       lv2:portProperty lv2:enumeration ;    
       lv2:scalePoint [rdfs:label "1/4note"; rdf:value 1];
       lv2:scalePoint [rdfs:label "Dotted1/8note"; rdf:value 2];
       lv2:scalePoint [rdfs:label "1/4notetriplets"; rdf:value 3];
       lv2:scalePoint [rdfs:label "1/8note"; rdf:value 4];
       lv2:scalePoint [rdfs:label "1/8notetriplets"; rdf:value 5];
  • When you’re done, exit nano:
Ctrl + x
  • select Y(yes) or N (no)
  • Enter
systemctl restart mod-ui
  • Enter
  • CAUTION: Delete your cache Browser to be shure to see the changes on your GUI

If all goes well, your modified Gen-based plugin should now be inside the MOD device, ready to be played!


There is another process which is different from the process described above. It doesn't use the MOD Duo-package in Max.

Compiling the plugin

First, download and extract it.
Send an "exportcode" message to the gen~ object in your main Max-patcher to get the YOURPLUGIN_NAME.cpp and YOURPLUGIN_NAME.h files.
replace YOURPLUGIN_NAME with “gen_exported" for both files Copy the gen_exported.cpp and gen_exported.h files into the extracted max-gen-deploy folder, and run:

$ cd /path/to/max-gen-deploy/
$ ./

You'll be asked for a plugin name, and after providing one the cloud should give you back a tar.gz file within a few minutes.

Editing the plugin

To add units, knob behavior or a description, you'll have to edit the .ttl file. If you do so, make sure everything is correct,
otherwise the plugin won't work and you might have to SSH into the MOD Duo to get the corrupt plugin out.
To prevent this from happening, you can validate the lv2-data.

The other option is to include a GUI, you can make one with the MOD SDK.
Have a look here how a GUI affects the .ttl structure.

$ tar -xzvf Plugin.lv2-dwarf.tar.gz
make edits in Plugin.lv2/Plugin_dsp.ttl or include a GUI
$ rm Plugin.lv2-dwarf.tar.gz
$ tar -cvzf Plugin.lv2-duo.tar.gz Plugin.lv2/

Deploying the plugin

Make sure the MOD device is connected to your computer via USB before proceeding. Then run:

$ cd /path/to/max-gen-deploy/
$ ./