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MIDI Loupe

Official Description

MIDI Loupe allows you to monitor and log MIDI messages from one or multiple MIDI devices. It is mostly useful for debugging and testing your MIDI setup, if something goes wrong.

New in version 1.4: added time logging feature

Functions:
Every registered MIDI Source is listed and has a separate color, so you can easy differentiate between the messages. In the device list you can select/deselect the devices for logging.
You can save the logs to disk and also load them for later inspection.

Please also look at http://www.gfApps.com for more informations.