16.3. MIDI Output

Hydrogen allows you to send both notes encountered during playback as NOTE_ON and NOTE_OFF messages and the current state of specific controls using MIDI Feedback as CC messages.

But first of all you have to set a MIDI Output device in the Preferences.


The list of available MIDI output devices/ports is compiled for the current MIDI driver when opening the Preferences dialog. If you switch to another driver, be sure to click OK and reopen the Preferences dialog in order to have an updated list.

Now every note encountered during playback will trigger a MIDI note with the note's velocity and the channel and pitch specified in the corresponding instrument. In case the channel is set to off, no MIDI message will be sent.


To enable MIDI output, you have to set both an output device in the Preferences as well as all instrument MIDI channels to a dedicated value, like 10.

16.3.1. MIDI Feedback

You can also keep other MIDI-capable applications posted about parameter changes in Hydrogen using MIDI Feedback. If one or more CC events are mapped to a parameter supporting feedback, all of its changes - also those triggered by incoming MIDI messages - will cause Hydrogen to send a CC message. This message will carry the same message parameters as the one mapped to the particular parameter within Hydrogen and will contain its value mapped to a range between 0 and 127.

Supported feedback parameters are