Plugin Host

The Plugin Host node lets you load one of your own third-party VST3 plugins and use it right inside your MNodes patch, just like any other node. You can send audio and notes through it, control its settings from the Inspector, and move those settings automatically with CV.

Loading a plugin

Click the body of the node, or its Select Plugin button, to open the plugin chooser. Search by name or maker and click a plugin to load it.

Once a plugin loads, the node rebuilds its connection points to fit it: audio in and out for an effect, a note (MIDI) input for an instrument, and so on.

The plugin gives its pins their names, and a long one can be cut short. Drag the node's left or right edge to make it wider, so the names fit. It never goes narrower than 300.

Drag its top or bottom edge, or a corner, to make it taller. The extra height goes to the body, so the plugin's preview gets bigger. It never goes shorter than its pins need, and when a new pin comes in, the node grows by that row and the body keeps its size. The project keeps the size you give it.

A loaded plugin runs in its own separate background program. That is good news for you: if a plugin crashes or freezes, it cannot drag MNodes down with it. MNodes spots the problem and reloads the plugin on its own. (The one exception is a plugin you choose to run inside MNodes.)

The plugin editor

Click the preview area in the node's body, or the Open Editor button, to open the plugin's own window. It stays in front of the MNodes window. Click Close Editor, or the window's own close button, to hide it again.

In a DAW, closing the MNodes window also hides every plugin window you had open, those of Plugin Hosts inside Modules, Poly Modules and Subgraphs too, and opening MNodes again brings the same ones back in the same place. A big plugin may take a moment to draw its window again.

On a Mac, the plugin's window also stays in front of your DAW and its other plugin windows while you work there, and goes back among your DAW's windows when you switch to another app. With your DAW in full screen, it opens there too.

The preview in the node's body is a picture of the plugin's window, taken a moment after it opens and again when you close it.

To open and close the window from the patch, turn on Editor Input in the Inspector. The node gets an Editor input: a bang opens the window when it is closed and closes it when it is open, so a Widget Button on your Front Panel can show and hide the plugin, and a number or a toggle opens it at 1 and closes it at 0. A plugin that is still loading opens its window as soon as it is there. In a DAW with MNodes' window closed, it opens when MNodes' window opens. Off by default, and then the node has no such pin. New in MNodes 1.1.9.

Running a plugin inside MNodes

On a Mac the separate background program counts as an app of its own, and some DAWs react to that. In Bitwig, the moment you click in the plugin's window, the DAW hides MNodes' window: as far as it can tell, another app has just come to the front. Clicking back in the DAW brings it back, which makes the plugin hard to use.

Turn on Run Inside MNodes in the Inspector and the plugin runs inside MNodes itself, the way your DAW runs its own plugins. Its window then belongs to the same app as MNodes' window, so the DAW leaves both alone. The plugin's window stays in front of MNodes' window, and goes away and comes back with it.

Switching it on or off reloads the plugin with its current settings, and its window opens again if it was open. Everything else works as before: the plugin's settings in the Inspector, exposed pins, Input and Output Pairs, Unused Outputs, bypass and States. A large plugin can make MNodes pause for a moment while it loads, since it now loads in MNodes.

WARNING

Running inside MNodes gives up the protection described above. If the plugin crashes, it takes MNodes down with it, and your DAW too when MNodes runs inside one. Save your work before you try it, and leave it off for plugins you are not sure about. It is off by default, and each Plugin Host node has its own.

Plugin parameters

Select the Plugin Host node and the Inspector lists every setting of the loaded plugin, under Plugin Parameters. Drag a slider and the change reaches the plugin right away.

The two stay in sync both ways: move a control in the plugin's own window and the matching slider in the Inspector follows along. The Inspector also keeps track of the last setting you touched: that row is selected and scrolled into view automatically, so you never lose sight of the control you are adjusting, even on plugins with hundreds of settings.

Exposing parameters as pins

Each setting row in the Inspector has a small dot on its left. Click it to expose that setting, and the node grows two connection points for it:

• an input pin that takes a value or a CV signal. Wire an LFO, an envelope or a sequencer into it to move that plugin setting automatically in real time.
• an output pin that sends out the setting's current value, so other nodes or panel controls can stay in step with it.

A setting the plugin marks as read-only, one it cannot let the host automate, such as a meter it only reports, gets the output pin alone. Its row stays where it was, so the node is as tall as before. This is decided when you expose the setting, so a Plugin Host in a project made before 1.1.9 keeps every pin it had and its cables. To drop those unused inputs, click the setting's dot off and on again.

Click the dot again to remove that setting's pins. The node grows and shrinks as you add and hide settings, so the pins always have room.

Tempo sync

The loaded plugin picks up the timing (transport) from your DAW, or from MNodes' own transport when you run MNodes on its own. Plugins, arpeggiators and LFOs that lock to tempo will follow the song's position and speed automatically.

Where MNodes looks for plugins

MNodes searches your computer's system VST3 folders for plugins. To add or change which folders it searches, open Settings and find the Plugin Folders block.

Each plugin is tried in a separate background program, so one that crashes or freezes while it is being looked at cannot take MNodes down. A plugin that fails is tried once more at the end of the scan, on its own and with more time. If it fails again it is skipped, and the Plugin Folders block counts how many were. Show skipped lists them there by name, with the reason each one was left out (it took too long to answer, it crashed while it was scanned...), and a click on one shows it in its folder. Copy list puts that list on the clipboard, with your MNodes version and system, ready to paste into a message on the forum, and Show log file opens the folder with PluginScanLog.txt picked, for when you are asked for the whole log. Scan new plugins, and the rescan in the Plugin Host's plugin list, try the skipped ones again; Rescan all looks at every plugin from scratch. Every failure is also written to PluginScanLog.txt, in the MNodes settings folder (%APPDATA%\Mario Nieto\MNodes on Windows, ~/Library/Application Support/Mario Nieto/MNodes on a Mac).

Inputs and outputs

The exact connection points depend on the plugin you load.

Pin	Type	Direction	Shown when
In L / In R	Audio	Input	The plugin is an effect (hidden for instruments)
Extra input pairs	Audio	Input	You raise Input Pairs and the plugin has them
MIDI	MIDI	Input	The plugin accepts MIDI
Out L / Out R	Audio	Output	Always
Extra output pairs	Audio	Output	You raise Output Pairs and the plugin has them
MIDI	MIDI	Output	The plugin produces MIDI
Exposed parameter	Data / CV	Input	You expose a parameter the plugin lets the host automate (one pin each)
Exposed parameter	Data	Output	You expose a parameter (one pin each)
Editor	Data	Input	You turn on Editor Input (opens and closes the plugin's window)

Sidechains and extra inputs

Plenty of plugins take more than one stereo input: a compressor with a sidechain, a vocoder with a carrier and a modulator, a morphing effect with an A and a B. Those extra inputs are switched off until a host asks for them, which is why the node showed only In L / In R.

Raise Input Pairs in the Inspector and the extra pins appear, named after the plugin's own buses where it tells us what they are called, so you get a pin marked Sidechain rather than In 2. It works the same way Output Pairs already does: you ask for what you need rather than every plugin growing pins nobody wired. The plugin's own count still caps it, so asking for four pairs from a plugin that only has one gives you one.

An extra input you leave unwired is fed silence, which is exactly what a DAW does with an unconnected sidechain.

Extra outputs

The same idea on the way out. A drum machine that keeps its kick, snare and hats on separate outputs, or a sampler that gives each layer its own, has more than one stereo pair to offer, and the node shows one until you ask for more.

Raise Output Pairs in the Inspector and the extra Out pins appear, in the plugin's own order, so you can send each pair to its own chain. A plugin with a single stereo output gives you one pair however high you set it.

Unused outputs

Some instruments switch on every output they have and go on rendering all of them, whether or not anything is listening: Omnisphere runs nine stereo outputs by default. Your DAW does not work that way. Live, for instance, runs the main output and leaves the rest alone until you ask for them, which is why the same instrument can cost several times more inside MNodes than on a track of its own.

Unused Outputs, in the Inspector, is where you choose. Active keeps every output running, which is how MNodes has always behaved. Off keeps only the outputs you are actually using and switches the rest off, the way a DAW does.

What Off keeps is exactly what Output Pairs asks for, counting from the first. With Output Pairs at 1, the default, you keep the first stereo pair and everything above it goes quiet. At 3 you keep the first three pairs. The main output is never switched off whatever you set, and raising Output Pairs switches the ones you need back on there and then, without reloading the plugin.

WARNING

Active is the default on purpose. Two Steinberg instruments, HALion 7 and Groove Agent SE, crash inside their own processing when an output they declared is switched off. If a plugin goes quiet, glitches or disappears with Off, put it back to Active and it will behave. The setting belongs to that one node, so it costs nothing to try, and a plugin that cannot take it takes only itself down: it runs in its own process, not in MNodes (unless you turned on Run Inside MNodes for it).

Instruments and DC offset

Some instruments leave a constant offset (DC) in their output even when nothing is playing. You cannot hear it, but it holds a level meter up as if something were sounding. For an instrument, the Plugin Host removes it with a very gentle cut below 5 Hz.

An effect gets nothing of the kind: what it sends out is passed on exactly as it is. So an effect that does not change the sound gives back exactly what it was fed, which matters when you mix a processed branch against the original, for example to hear only what an EQ or a reverb adds.

An empty Plugin Host

A Plugin Host with no plugin chosen lets its audio straight through, the way an empty insert slot does in a DAW, so you can build a chain first and fill the slot later. While a plugin is loading, or if its background program has stopped, the node is silent.

TIP

Only VST3 plugins are supported. A plugin and its editor run in a separate process, so they cannot crash or freeze MNodes itself, unless you turn on Run Inside MNodes for that node.

When a plugin misbehaves

MNodes writes down what happens with every hosted plugin: when it loads, when its window opens, when its background program stops. If a plugin freezes, closes its window on its own or keeps reloading, open Settings > General, find Plugin logs and click Show folder. Zip the files you find there (MNodesPluginHost.log, MNHostWorker.log, and any file whose name starts with MNHostWorker-crash) and attach the zip to your report.