Quick answer: Liquid Notes works perfectly well with Reaper. Compatibility between the two applications has been tested in January 2014 on Mac OS X.
Routing for Reaper in Mac OS XPlease follow these steps to complete the routing setup for Liquid Notes in Reaper (v4.581).
Setting up an IAC-BusGo to: Applications → Utilities → Audio MIDI Setup. This opens the Mac utility Audio MIDI Setup.
From the menu Window select Show MIDI Window.
Double-click on IAC driver. For the routing to Reaper at least one bus should be created. If your project in Liquid Notes exceeds 16 channels, set up additional IAC busses.
Activate Device is online.
Importing a MIDI file and setting up Liquid Notes to connect with ReaperDrag and drop the resulting MIDI file onto the Welcome screen of Liquid Notes and choose Other sequencer when asked for the sound output. Liquid Notes will now take to through windows concerning track types and lets you know that it faces an unknown sequencer. Just ignore and click Next.
At Routing Settings select your IAC Bus for the out-port and make your choices for the respective out-channels and instrument selections. Liquid Notes will now perform the analysis of the imported MIDI file.
Getting Reaper ready to receive input from Liquid NotesFire up Reaper. Go to Preferences and click on the Audio tab on the left side to select MIDI Devices. Enable the IAC Bus 1 by double-clicking on its name and making your choices in the opening window. Make sure to at least check Enable input from this device. Now hit Apply and Reaper’s connection to Liquid Notes is established.
Now set up the number of required tracks and insert your favourite plugins: From the Track menu select Insert virtual instrument on new track. Make your choices as to the plug-in you wish to use. At the track header’s input selector select Input → MIDI → IAC Bus 1 → corresponding channel number. Record arm the track (hit the little button to the left of the plugin’s name) and make sure that the FX button is activated and lit up in green. Repeat these steps for every track in your arrangement in Liquid Notes.
You are good to go. Hit Play in Liquid Notes and have fun.
Exporting a MIDI project from Reaper for analysis and production in Liquid NotesSimply export your arrangement from Reaper as MIDI file and open it in Liquid Notes simply by choosing and selecting the tracks in Reaper you wish to export. From the File menu select Export Project MIDI… In the following Consolidate MIDI dialogue make your choices as to how you want your MIDI exported - in most cases you will want to make sure to choose Multitrack MIDI file.