First we need to create a fixed MIDI Loopback Port. See below for setup per platform…
macOS
Uses Apple’s built-in IAC Driver. One-time setup at the OS level — any MIDI-aware app then sees the bus regardless of launch order.
One-time setup:
Open Audio MIDI Setup (in /Applications/Utilities/, or via Spotlight).
Menu: Window → Show MIDI Studio.
Double-click the IAC Driver icon.
Tick Device is online at the top.
Under Ports, add a port named TWEAKER (use the + button if no ports are listed). Click Apply.
Every session:
In your DAW: set the MIDI Hardware Output or track MIDI input to IAC Driver TWEAKER.
In TWEAKER: the MIDI In dropdown can stay on All MIDI Inputs (default) or be set explicitly to the IAC bus.
Troubleshooting:
IAC Driver icon missing from MIDI Studio: it’s built into macOS but may have been hidden. Try the View menu’s Show All toggle, the configuration dropdown (switch away from “Default” and back), or the + button to re-add it. Last resort: quit Audio MIDI Setup, run sudo killall coreaudiod in Terminal, then reopen Audio MIDI Setup.
IAC Driver shows red/disabled and won’t open: single-click to select it first, then click the ⓘ Info button in the MIDI Studio toolbar (or right-click the icon) and tick Device is online. Icon turns blue and double-click then opens properties.
Single-click still doesn’t select IAC Driver after enabling: quit Audio MIDI Setup and relaunch it — MIDI Studio sometimes needs a restart before the newly-enabled device responds.
Windows
Windows 11 build 24H2 or newer required — the new Windows MIDI Services aren’t available on Windows 10 or earlier Windows 11 builds.
One-time setup:
Install Microsoft’s Windows MIDI Services SDK Runtime and Tools (~220 MB). TWEAKER’s MIDI dropdown has a “How to use MIDI from a DAW…” entry with a Download Now button that takes you here.
Launch the Windows MIDI and Musician Settings app from the Start menu.
Click the blue Finish MIDI Setup button at the top; restart Windows if prompted.
Click Set MIDI Service to auto-start at boot so the service is ready before basehead launches.
(Optional) Under MIDI 2.0 Loopback Endpoints, click Create New Loopback Endpoint Pair and name them TWEAKER A / TWEAKER B. If you skip this, the built-in Default App Loopback (A)/(B) pair works just as well — TWEAKER shortens these to Def. Loopback (A)/(B) in its dropdown.
Every session:
In your DAW: set the MIDI hardware output to Default App Loopback (A) (or TWEAKER A if you made your own pair).
In TWEAKER: the MIDI In dropdown can stay on All MIDI Inputs (default), or be set explicitly to Def. Loopback (B) (or TWEAKER B).
The ● dot next to MIDI In: in the TWEAKER header blinks on each incoming MIDI message — quick way to confirm receive is alive.
Troubleshooting:
No loopback entries in TWEAKER’s dropdown: re-run “Finish MIDI Setup” in the Windows MIDI Settings app, and confirm a loopback pair exists under “MIDI 2.0 Loopback Endpoints”.
Entries show up but notes don’t arrive: in the MIDI Settings app, Active Sessions should list both basehead and your DAW as open clients of the loopback endpoints.
Worked, then stopped after relaunching the DAW: occasionally Windows MIDI Services keeps stale handles to changed endpoints. Quit and relaunch both the DAW and basehead.