REAPER

REAPER opens items in HARP as an external editor.

Link HARP

1. Open REAPER's preferences (Ctrl+P on Windows and Linux, Cmd+, on macOS).
2. Select External Editors, at the bottom of the list, and click Add.
3. Leave File type (extension) blank to make HARP the default editor for every file type, or enter an extension such as wav to use HARP for that type alone.
4. Click Browse... beside Primary Editor, and select HARP, e.g., /Applications/HARP.app on macOS. Click OK in both windows.

Open Audio in HARP

1. Right-click an item, and choose Open items in editor > Open item copies in 'HARP.app'. The menu names the file you selected as the editor, e.g., HARP.exe on Windows. REAPER opens a copy of the item, which leaves the original untouched, while Open items in 'HARP.app' opens the original.

   

2. Process the DAW-linked track and send the result back, as in The Round Trip.

To process part of an item, split it, then select the excerpt and choose Glue items, which gives it a file of its own.