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I'm trying to figure out a way to use Hydrogen (on OS X) to trigger external sound source (a hardware sampler). I have a Midiman MidiSport 2x2.

Would Hydrogen recognise a AU plug-in called MIDIO?
(scroll all the way down)

My set up would be Midi pads (M-audio Trigger Finger, either through USB or Midi on MidiSport ) -> Hydrogen (to sequence Midi events) -> Akai s2000 (a hardware sampler, via Midi). I'm hoping that this would allow for a work-flow similar to MPC2000.

Thanks for reading my post.



Joined: 03/30/2010


Hydrogen uses coremidi, so if you're interface is supported by coremidi, hydrogen should be able to output midi notes to it.
Can you choose your interface in the midi dialog of hydrogen?

neil82 (not verified)

Hi mauser,

Thank you very much for your reply!

I plugged in MidiSport, and Audio Midi Setup in OS X 10.5 recognises the Midi interface.

In Hydrogen, however, I only have have options ALSA, PortMidi and CoreMidi in the Midi driver drop-down box under Midi System tab. Would MidiSport appear in this drop-down box if it was working correctly?

Thanks again for your prompt reply.

Joined: 03/30/2010

Hi Neil!

You should choose "CoreMidi" as the midi device. You can then route the midi signals with the help of this OS X midi manager, at least i guess so :)
Never used it :-/

neil82 (not verified)

Hi mauser,

Thank you for your response!

I have everything connected:

Midi pads >>>>Mac >>MIDI Sport 2x2 >>> Akai s2000.

I can see midi pads and mac are communicating and in fact, I can trigger drum samples in Hydrogen.

Hydrogen, however, doesn't seem to be communicating with s2000. Midi events within Hydrogen isn't triggering the sound in s2000. I have selected CoreMidi in the Midi Driver drop down box.

I also created an external module in Audio Midi Set-up in OS X and connected it's midi-in to Midi Sport's Midi out.

Is there anything else that I need to do in order to get Hydrogen to communicate with s2000?

Joined: 03/30/2010

Hi Neil!!

I'm not sure if midi output is implemented in the CoreMidi-Driver of Hydrogen, i remember that it made some problems. Midi output is a relatively new feature of hydrogen, we have added it in the last year.
But i will put this on my todo list and report back here if i have any hints or a solution for you problem. At the moment i can't say if it's not implemented, a bug or a configuration problem. Sorry!

neil82 (not verified)

Hi mauser,

Thank you for your quick reply! Yes, please let us know if and when you find out. It would be great to be able to use Hydrogen as a sequencer as it has everything that I want from a sequencer (eg layering notes).

Please keep up the great work!

neil82 (not verified)

Hi mauser,

I found this from Google.

This email group was from january 2009. Do you know what has happened to Midi out implementation? Is the Midi out branch still up and running, or has it been incorporated into the main version of Hydrogen?

By the way, do I need to have Jack installed to get Midi out working in CoreMidi?

Thank you again for your help in this!

wolke's picture
Joined: 03/30/2010

midi out is only available for alsa!!! the coremidi code for midi-out on a mac is not finished yet.

midi-out is an feature in trunk (0.9.5)


example code is in alsa_midi_driver.cpp
it must ported to the other drivers.

neil82 (not verified)

Hi wolke,

Thanks for your clarification. I will be eagerly waiting for0.9.5...!