Drumstick MIDI Monitor is a MIDI monitor for Linux using ALSA sequencer and Qt5 user interface.

Features:

• Easy to use Qt5 graphic user interface
• Based on ALSA sequencer. Provides one input port to be connected to other programs and devices using the usual external tools (aconnect, QJackCtl…)
• Customizable event filters and sequencer parameters
• Supports all MIDI messages, including System Exclusive, and some ALSA messages
• MIDI Playback of the recorded session or loaded MIDI file
• Saves to a text file or standard MIDI file the recorded event list

sourceforge.net/projects/kmidimon/