Download Synchain Bridge VST3 / AU / AAX plug-in

How it works

The plug-in encodes nothing of its own and changes nothing about the sound on your DAW track. It simply forwards the audio block by block, exactly as the DAW hands the buffers over, to a WebSocket service on your own machine; Creative Space in the browser connects to that local service and streams the audio on to everyone in the room.

DAW → Synchain Bridge → local WebSocket → browser → real-time audio server → collaborators

Requirements

• Windows x64 — 64-bit Windows 10 or 11. The plug-in interface is drawn with the WebView2 runtime: Windows 11 already ships with it; on Windows 10, install the Evergreen runtime if it is missing.
• Apple Silicon Mac — macOS 11.0 or later on an M-series chip (arm64 only; there is no Intel build). Your DAW must run natively on Apple Silicon — a host running under Rosetta cannot see the plug-in. The build is not signed or notarized, so a one-off xattr command is needed before the first load (see the macOS steps below).
• A VST3- or AU-capable DAW, such as Reaper, Ableton Live or Cubase. On macOS, Logic Pro loads the Audio Unit (AU) build instead. GarageBand only accepts sandbox-safe Audio Units and is not supported.
• A Synchain account that is an admin or a member of the project in question — viewers can only look, they cannot enter the room.
• Avid Pro Tools (AAX, Beta) — 64-bit Pro Tools (AAX Native) on Windows 10 or 11 x64, using the separate AAX download. The AAX build is PACE-signed, so regular Pro Tools loads it; the macOS AAX build has not been released yet.

Installing on Windows

1. Download and unzip

   Unzip the archive and you get a folder named Synchain Bridge.vst3. Note that it is a bundle directory, not a single file.

2. Put it in the VST3 folder

   Copy the whole Synchain Bridge.vst3 folder into C:\Program Files\Common Files\VST3\ (administrator rights required). If you would rather leave the system folder alone, keep it anywhere you like and add that location as a VST3 scan path in your DAW. When upgrading, delete the old Synchain Bridge.vst3 folder first, wherever you put it: copying the new one over it merges the two folders and leaves files from the old version behind.

3. Make the DAW rescan

   Open your DAW and rescan its plug-ins. Synchain Bridge uses its own manufacturer code Snch and plug-in code Snb1, so the DAW picks it up as a brand-new plug-in.

4. Insert and connect

   Insert Synchain Bridge on a stereo track or bus that is carrying sound and click Start. Then open your project's Creative Space in the browser — normally it connects on its own. If it does not, type the port shown in the plug-in panel into the DAW audio bridge settings in the browser.

Installing on macOS

1. Download and unzip

   Unzip the archive and you get two bundle directories: Synchain Bridge.vst3 (the VST3) and Synchain Bridge.component (the Audio Unit). Both are folders, not single files.

2. Copy the bundles into your user plug-in folders

   Drag Synchain Bridge.vst3 into ~/Library/Audio/Plug-Ins/VST3/ and Synchain Bridge.component into ~/Library/Audio/Plug-Ins/Components/. Both folders are user-level, so no administrator rights are needed (create them if they do not exist yet). When upgrading, delete the old Synchain Bridge.vst3 and Synchain Bridge.component from those folders first: ditto merges into an existing bundle and would leave files from the old version behind. If you prefer the Terminal, first cd into the folder you unzipped in step 1 (the two ditto commands use relative paths; if ditto says the file does not exist, you are not in that folder yet: cd into it and rerun from the first ditto command). The commands below remove the old bundles (harmless on a first install), copy the new ones with ditto, which keeps the executable bits intact, and finally stop AudioComponentRegistrar to clear the cached Audio Unit info, so your DAW does not keep seeing the old version. If that last command reports No matching processes, it was simply not running and you can ignore the message:

   rm -rf ~/Library/Audio/Plug-Ins/VST3/"Synchain Bridge.vst3"
   rm -rf ~/Library/Audio/Plug-Ins/Components/"Synchain Bridge.component"
   ditto "Synchain Bridge.vst3" ~/Library/Audio/Plug-Ins/VST3/"Synchain Bridge.vst3"
   ditto "Synchain Bridge.component" ~/Library/Audio/Plug-Ins/Components/"Synchain Bridge.component"
   killall -9 AudioComponentRegistrar

3. Remove the quarantine flag

   The build is not signed or notarized, so Gatekeeper blocks it on first load. Run these two commands once in the Terminal (the plug-in is then trusted for good):

   xattr -dr com.apple.quarantine ~/Library/Audio/Plug-Ins/VST3/"Synchain Bridge.vst3"
   xattr -dr com.apple.quarantine ~/Library/Audio/Plug-Ins/Components/"Synchain Bridge.component"

4. Make the host rescan

   Open your DAW and rescan its plug-ins: Logic Pro picks up the Audio Unit, while Reaper, Live and Cubase use the VST3. The host must run natively on Apple Silicon — not under Rosetta, or it will not find the arm64 plug-in. To check the AU from the Terminal, run the validator; it should end with AU VALIDATION SUCCEEDED:

   auval -v aufx Snb1 Snch

5. Insert and connect

   Insert Synchain Bridge on a stereo track or bus that is carrying sound and click Start. Then open your project's Creative Space in the browser — normally it connects on its own. If it does not, type the port shown in the plug-in panel into the DAW audio bridge settings in the browser.

Installing the AAX in Pro Tools (Windows, Beta)

1. Quit Pro Tools and unzip

   Quit Pro Tools first, then unzip the archive. You get a folder named Synchain Bridge.aaxplugin: it is a bundle directory, not a single file, and it is PACE-signed — copy it as a whole and never add, remove or edit anything inside it, or the signature breaks and Pro Tools will not load it.

2. Replace the old version in the Avid plug-in folder

   Pro Tools scans a single folder, C:\Program Files\Common Files\Avid\Audio\Plug-Ins\, and has no per-user folder, so this step needs administrator rights. When upgrading, delete the old Synchain Bridge.aaxplugin there first: copying the new one over it merges the two folders and leaves files from the old version behind. Copy the new folder into Plug-Ins itself, not into the old bundle, or it ends up nested one level too deep. File Explorer works, or use a PowerShell window opened as administrator: first cd into the folder you unzipped in step 1 (the copy command uses a relative path; if Copy-Item says it cannot find the path, you are not in that folder yet: cd into it and run both commands again). The first command removes the old bundle and is harmless on a first install; the second copies the new one in:

   Remove-Item "$env:CommonProgramW6432\Avid\Audio\Plug-Ins\Synchain Bridge.aaxplugin" -Recurse -Force -ErrorAction SilentlyContinue
   Copy-Item ".\Synchain Bridge.aaxplugin" "$env:CommonProgramW6432\Avid\Audio\Plug-Ins\" -Recurse -Force

3. Restart Pro Tools and insert it

   Start Pro Tools again and open an insert slot on a mono or stereo track, an Aux or the Master, then look the plug-in up by name: Synchain Bridge. If your plug-in menus are organized by category, it is under Other. Windows shows the self-signed certificate of the AAX build as untrusted (Properties → Digital Signatures); that is expected and does not stop Pro Tools from loading it.

4. Start and connect

   Click Start in the plug-in panel. Then open your project's Creative Space in the browser — normally it connects on its own. If it does not, type the port shown in the plug-in panel into the DAW audio bridge settings in the browser.

Known limitations (Beta)

• Mono and stereo inserts only: there is no AudioSuite version and no multi-mono variant.
• Offline rendering does not stream: during an offline bounce, Track Commit or Freeze the audio passes through untouched and nothing is sent to the browser; streaming resumes when the render ends.
• Dynamic Plug-in Processing may pause the stream: when no audio reaches the plug-in (a muted or silent track), Pro Tools can stop calling it until audio flows again.
• The panel's buffer and latency reading always reflects 1024 samples (about 21.3 ms at 48 kHz), the AAX maximum block size, not your hardware buffer size.
• If Pro Tools uses the computer's built-in sound card, it takes that device exclusively, so a browser on the same computer may play no sound. Streaming to the room is not affected and the others still hear you; to listen locally, use a separate audio interface or set the browser's output to another device.
• If you move the plug-in window to a monitor with a different display scaling, close the window and open it again.
• Only the first instance is reachable on the default port 9420; further instances take 9421–9429, so enter that port in the web app.

Avid, Pro Tools and AAX are trademarks or registered trademarks of Avid Technology, Inc. PACE and iLok are trademarks of PACE Anti-Piracy, Inc. Synchain Bridge is an independent project, not affiliated with, sponsored or endorsed by Avid.

Good to know (both platforms)

The plug-in starts a local WebSocket service on 127.0.0.1:9420. If that port is taken it retries automatically across 9420–9429, and the panel tells you which port it ended up on.

Use Chrome, Edge or Firefox to open Creative Space. Safari blocks HTTPS pages from connecting to ws://127.0.0.1, so it cannot reach the plug-in on a Mac. If your browser asks to access other apps and services on this device, choose Allow; if you blocked it earlier, switch it back to Allow from the site information icon at the left of the address bar.

Open source & checksums

59e83d0c91102a6fca7f9f6e195b8298d896fdc0443f391c9ab55afc26fd6914

certutil -hashfile SynchainBridge-VST3-v1.6.0-win64.zip SHA256

d2d8978fab9b85b7aa4b878b4260df7a50b861638af60f48cbabd954b1c2cd9b

shasum -a 256 SynchainBridge-VST3-AU-v1.6.0-macos-arm64.zip

96bf312bd555b88cfe9fafcac5c5a1850121d2adf32271e48a50ccef80e910d6

certutil -hashfile SynchainBridge-AAX-v1.6.0-win64.zip SHA256

Nothing to install on the web side

Everything else in Synchain runs in the browser: sign in and you can enter a project, open Creative Space, browse files and check the calendar and discussion. A client or partner joining as a listener just opens the invite link — no software at all.