# 20. External Plugin System (EPS) - Documentation #### COMING SOON! [Contact us](https://mpmidi.com/contactus) if you want to join the Beta program. --- Large DAW templates spend most of their loading time creating plugins and restoring their state: samplers reload gigabytes of samples, and big effect chains are rebuilt every time a project opens, only to be destroyed again when it closes. EPS removes that wait. It is for composers, producers and mix engineers who work with large orchestral (ie Kontakt) or production templates, switch between many projects or song versions, or use the same instruments and effect chains across projects, and who want to control those plugins with MP Controller. With EPS, the plugins live in the EPS Server instead of the DAW project: you load them once, they stay loaded while you close one project and open the next, and each project reconnects to them in moments. The DAW project still saves the full state of every plugin, so a project always opens the way it was saved, and a plugin crash stays in its own instance instead of taking down the DAW. Additionally, the system has the ability to load plugins on demand, when the DAW project opens. **Intended use** - **Persistent templates** – load an orchestral or production template once in the server, save it as a server project and open it automatically at startup. Every DAW project that uses it connects in moments instead of reloading it. - **Switching projects and song versions** – close one project and open the next (an alternate mix, the next cue, a revision) without reloading the shared instruments and effects. - **Sharing instruments across projects** – several projects use the same server instances, for example the same sampler setup for every cue of a film score. - **Stability** – each instance runs in its own process, so a crashing plugin does not crash the DAW or the other instances, and the instance can be restarted from its last snapshot. - **Hardware control** – every slot is an MP Single Host, so MP Controller's automatic parameter mapping, Plugin Panel and encoders work for EPS instances exactly as for MP Host. - **AudioGridder-style use** – with DAW Load Mode on, instances are created and removed with the DAW project, for when the server should only host plugins outside the DAW. **How it works** EPS (External Plugin System) keeps your plugins loaded in a separate application, the **EPS Server**, independently of your DAW projects. In the DAW, the **EPS Client** plugin connects a track to one of these server instances. Closing a project only disconnects the tracks; when you open the project again, the tracks reconnect to the instances that are still loaded, without reloading the plugins. Every slot in an instance is an MP Single Host, so MP Controller's automatic parameter mapping and hardware control work as usual. ![EPS Server window](https://kb.mpmidi.com/uploads/images/gallery/2026-10/fNlNlC3qkuSsfSN3-embedded-image-2uqsuixw.png) ##### Components - **EPS Server** – a stand-alone application with its own window and a menu bar icon. It owns the instances and their plugins. - **EPS Client** – the plugin you insert in the DAW, in two variants: **EPS FX** (effects) and **EPS Inst** (instruments). Available as VST3, AU and AAX. - **Instance** – a container on the server with up to 12 slots, of type *Instrument* or *Effect*. One client track connects to one instance. - **Slot** – one MP Single Host inside an instance, hosting one plugin. ##### License The EPS Server uses your MP Controller license (the same license as MP Host). The license is checked when the server starts. If it is missing or invalid, the server shows *MP Controller license not found or invalid. Run the MP license manager.* and quits. Activate or repair the license with the MP license manager, then start EPS Server again. ##### Starting the server - Start **EPS Server** like any application. To start it automatically, turn on *Settings > Start at login*. - The server window opens at start. Click the **menu bar icon** to show or hide the window. Right-click, Control-click or Option-click the icon for its menu. - Instances do not survive quitting the server. To get the same instances back at the next start, save a server project and set it under *Settings > Open at startup*. ##### The server window **Toolbar** ![Toolbar](https://kb.mpmidi.com/uploads/images/gallery/2026-10/MO8fbh1r2faGt9zI-embedded-image-zyhrarvi.png) - **New Project** – removes all instances and starts an empty project. - **Open...**, **Save**, **Save As...** – server project files (`.epsproj`, default folder *Documents/EPS Projects*). - **+ New Instance** – creates an instance (see *Creating instances*). - **Disconnect All** – disconnects every connected DAW track. - **Settings** – the server settings. - On the right: the number of instances and connected instances, the default sample rate and block size, system CPU, RAM used by the server and its instances, and the network port. **Instance list (left)** ![Instance list with folders](https://kb.mpmidi.com/uploads/images/gallery/2026-10/ZpDp9u6utHbh0uhe-embedded-image-cbcy25v9.png) - Each row shows the instance colour, name, a plugin format badge (VST, VST3, AU), the type and the plugins in its slots, the state, MIDI and audio activity lights, and its CPU use. - States: *Connected* (a DAW track is using it), *Not connected*, *Loading* and *Crashed*. - **Search** filters by instance and plugin names. **A-Z** sorts alphabetically. The *Instruments* and *Effects* chips hide that type. - **Drag** rows to reorder them. The connect dialog in the DAW shows instances in this order. - **Double-click** a name to rename it. **Alt-click** a row to open the MP Single Host window of its last active slot. - **Hover** over a row for a moment to see a preview of its slots, with plugin names, vendors, power and bypass state and CPU. - **Right-click** a row for Rename, Colour, Preserved, Decoupled, Reconcile policy, Move to Folder, Disconnect, Restart (crashed instances) and Delete. - Each row has a **power** and a **bypass** button (see *Power and bypass*). - When you switch to a slot of another instance with MP Controller (Plugin Panel or *Select Plugin* in MP Host), the server window selects that instance. **Folders** - Folders group instances in the list; they do not change how instances work. Create one with the folder button at the top of the list, or with *Move to Folder > New Folder...* in an instance's menu. - Click a folder to open or close it, double-click to rename it. Its right-click menu has Open/Close, Rename, Move Up/Down and *Delete Folder* (its instances move to the top level). - Drag an instance onto a folder to put it in, or between rows to place it. Drag a folder to reorder folders; its instances move with it. - A folder's power and bypass buttons switch all its instances. Instances are switched one after another, so a large folder does not load all at once; the folder shows the progress (for example *Powering on 3/12*). - Folders are saved in the server project. **Instance view (right)** ![Instance view with the slot table](https://kb.mpmidi.com/uploads/images/gallery/2026-10/Rz11aQLMpmmJX8sF-embedded-image-fdbm4dvh.png) - **Header:** colour, name, type, channel layout, and *Rename*, *Disconnect*, *Restart* and *Delete*. The status line shows the connected DAW and track. Below it: *Preserved*, *Decoupled* and the instance's *Policy*. - **Slot table:** slot number, plugin with format badge and vendor, Bypass, SC (sidechain), CPU, status, **Open**, move up/down and remove. **Open** shows the slot's MP Single Host window and changes to **Close** while it is shown. Alt-click or double-click a slot number to open its window. The active slot is highlighted. - **+ Add Slot...** opens the plugin chooser. - **Footer:** connected or not connected since, last snapshot, latency, memory, process ID, the current project, the startup project and the EPS version. ![Footer](https://kb.mpmidi.com/uploads/images/gallery/2026-10/J7nVnhFZAprs8a4J-embedded-image-9puq5gii.png) ##### Creating instances **+ New Instance** opens a dialog with: ![New Instance dialog](https://kb.mpmidi.com/uploads/images/gallery/2026-10/ZosJAqz5blBQRLI5-embedded-image-nlngeuwa.png) - **Name** – unique on the server; filled in from the chosen plugin. - **Type** – *Instrument* or *Effect*. - **Layout** – Instruments: Stereo, 8×Stereo or 16×Stereo outputs. Effects: Mono or Stereo, with or without sidechain. - **First plugin** (optional) – pick it from the plugin list. Double-click a plugin to create the instance at once. - **Preserved** – on by default. A new instance runs at the default sample rate and block size from the settings, and adapts to the DAW's settings when a track connects. ##### Plugin list - EPS uses MP Host's scanned plugin list. To scan new plugins, open any slot's MP Single Host window and scan from its Plugin List; EPS picks up the new list automatically. *Settings > Plugin list* shows the number of effects and instruments found. - The chooser has search and the tabs *All*, *Favourites*, *Recent*, *VST3* and *AU*. Right-click a plugin to add or remove it from favourites. - Choosing *None* adds an empty MP Single Host; its window opens so you can pick a plugin there. - Whether a newly loaded plugin's parameters are linked to the controller follows MP Host's own **Auto Map** setting (Tools menu of an MP Single Host window). ##### Power and bypass - **Instance power off** unloads all its plugins: their windows close, memory is freed and they leave the MP Plugin Panel. Their state is kept. Power on loads them again with the same settings. A powered-off instance outputs silence and uses no CPU. - **Slot power off** does the same for one slot; the audio passes through it. - **Instance bypass** bypasses every slot (latency is kept). **Slot bypass** bypasses one slot and is shown in the DAW client too. - All of these work while a DAW is connected. The DAW client shows a powered-off slot dimmed, as *Off - unloaded on the server*. ##### Server projects - A server project (`.epsproj`) stores all instances with their order, folders, colours, settings and the full state of every slot. - Use server projects for templates: load your orchestra or effect template once, save it, and let it open at startup. - *Settings > Open at startup*: *None*, *The last project* (the project opened or saved last) or *This project* (choose a file). - When you quit with unsaved changes, the server asks whether to save the project. ##### Using EPS in the DAW 1. Insert **EPS Inst** on an instrument track (or **EPS FX** on an audio track or bus). 2. Click the instance button in the plugin header to open the **connect dialog**. 3. Choose one of: - a **loaded instance** → *Connect*; the track uses that instance with its plugins as they are, nothing is reloaded. - an **available plugin** → *Create*; a new instance named after the plugin is created with it, and its MP Single Host window opens. - **<New empty instance>** → *Create*; an empty instance with the name from the name field (default: the track name). 4. Add or change slots from the client (*+ Add slot*) or in the server window. A freshly inserted client connects by itself only to a not-connected instance named like the track. Otherwise it shows *Not connected - Click to choose an instance* until you pick one (unless DAW Load Mode is on). **Connect dialog** - Lists the server's instances of the client's type (instrument clients see instrument instances, effect clients see effect instances), then the available plugins. Search filters names, plugins and manufacturers. - Each instance shows its state, type, plugins and where it is connected (*this track* or *attached: track - DAW*). Crashed instances are greyed out. - Picking an instance used by another track offers **Take over**. The other track then shows *Taken over, click to reconnect*. - Selecting this track's own instance offers **Rename**. **Client window** - **Header:** instance colour, the instance button (connection light, name, server project), the type and channel layout, the server's name and address with a connection light, the **Preserved** and **Decouple** toggles, and the menu. - **Slot rows:** number, format badge, plugin and manufacturer. Instruments: **M** (mute/bypass) and **S**; effects: **SC** (sidechain) and bypass; then the automation button. Move Up, Move Down, Delete and Automation are in the slot menu (automation button or right-click). - Click a slot to open its MP Single Host window. Opening the client window reopens the slot that was shown last (or the first usable slot). - **Footer:** latency, buffers, sample rate and block size, version. - Banners report a crashed instance and an automatic copy (see *Duplicated tracks*). **Instance names** - **Automatic Instance Rename** (client menu, on by default) names the instance after the DAW track and follows track renames. Names stay unique on the server: a second track called "Strings" gets "Strings 2". - **Rename Instance...** (client menu) renames the instance and the track name together, for DAWs that do not report every track rename (for example Ableton Live). Return applies, Escape cancels. ##### Saving and reopening DAW projects - When the DAW saves, each client stores its instance reference and the state of every slot in the DAW project, so the project is complete even without a server project. - When you close the project, the tracks disconnect. **Preserved** instances stay loaded on the server; instances that are not preserved are removed. - When you open the project again, each track reconnects to its instance. Slots that are unchanged are kept as they are, without reloading. If an instance is missing on the server, it is created again from the state in the DAW project. - If a slot on the server differs from the DAW project, the **reconcile policy** decides: - **DAW wins** (default) – the slot takes the state saved in the DAW project. - **Server wins** – the server's state is kept. - **Ask** – currently keeps the server's state. The default is set in Settings; each instance can override it (*Policy* in the instance header or right-click menu). **Preserved and Decoupled** - **Preserved** – the instance stays loaded when its DAW track disconnects. On by default. Off: the instance is removed when the track disconnects. - **Decoupled** – the DAW project stores only the reference to the instance, not the slot states; the server (and its server project) is the only source of the sound. The policy is then always *Server wins*. Use it for large shared templates; save the server project to keep their state. - Both can be changed from the client header or the server window. **Duplicated tracks** When you duplicate a track in the DAW, both copies refer to the same instance. The second one gets an automatic copy of the instance (named for example "Strings 2"), and the client shows a notice. *Settings > Busy timeout* sets how long the server waits before deciding that the instance is in use. ##### DAW Load Mode Turn on *Settings > DAW Load Mode* to let instances live with the DAW project instead of the server, like AudioGridder: - A DAW project creates its instances when it loads, and they are removed when it closes. - The DAW project's state always wins. - A new client on a track always gets its own instance. - Instances created in the server window or from a server project stay as they are. While it is on, the *Preserved* setting and the reconcile policy buttons in Settings are disabled. ##### Settings ![Settings window](https://kb.mpmidi.com/uploads/images/gallery/2026-10/bPzlc9sQvXNLmLGz-embedded-image-kesvkfhn.png) **Server** - **Server name** – the name clients see. - **Server ID** – the server's ID and network port (shown only). - **Start at login** – opens EPS Server when you log in. - **Quit** – ask before quitting while instances are loaded. **Project** - **Open at startup** – None, The last project, or This project (Choose...). - **Auto-snapshot (crash recovery)** – every 10, 30 or 60 minutes, or Off. Instances also save a snapshot when their track disconnects. **Instances** - **Default for new instances** – sample rate and block size. - **Reconcile policy** – DAW wins, Server wins or Ask (hover for an explanation). - **Instances created by a DAW** – keep them when the DAW disconnects (preserved). - **DAW Load Mode** – see above (hover for an explanation). - **Load at most** – how many instances load at the same time when a project opens. - **Busy timeout** – seconds before a second track gets a copy of an instance in use. **MP Host** - **Plugin list** – the number of effects and instruments in MP Host's scanned list. ##### Crashes and recovery - Each instance runs in its own process. If a plugin crashes, only that instance shows *Crashed*; the other instances and the DAW keep running. - **Restart** (instance header or right-click menu) loads the instance again from its last snapshot. - A DAW track that reconnects to a crashed instance restores it from the state saved in the DAW project. ##### Troubleshooting - **The server quits right after start with a license message** – run the MP license manager and check the MP Controller license. - **The client shows *Waiting for server...*** – start EPS Server. The client keeps trying and connects when the server is up. Effects pass audio through, instruments are silent until then. - **The client shows *Not connected - Click to choose an instance*** – no instance matched the track; click and pick or create one. - **The client shows *Taken over, click to reconnect*** – another track took the instance. Click to choose an instance, or pick the same one to take it back. - **The client shows *Deleted on the server*** – the instance was deleted in the server window. Choose or create another instance. - **A new plugin does not appear in the chooser** – scan it in an MP Single Host window's Plugin List.