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Roland TD-9 Midi to Hydrogen truncated audio

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Alan Electron
Alan Electron's picture
Joined: 02/06/2016

Roland TD-9 Midi to Hydrogen truncated audio

Equipment and Software

  • Roland Percussion Sound Module TD-9 ver 1.0 upgraded to ver 2.0 firmware
  • eBay MIDI USB lead
  • Toshiba Satellite A200 Laptop (2007)
  • Linux Mint ver 17.3
  • aj2midid ver 8
  • mididings ver 20120419
  • Hydrogen
  • qmidiroute ver (optional)


After suitable manipulation of instrument mapping in Hydrogen and testing the sounds with the mouse on Hydrogen mixer, a nice sounding drum kit was achieved. However, after connecting the TD-9 the drum sounds were truncated, in duration, when triggered with the TD-9 pads.

The qmidiroute display verified that the hitting the pads on the TD-9, sends the appropriate midi note-on, channel-note-velocity midi message but half a second later sends the midi note-off message. It is this note-off midi message that is truncating the percussion audio duration, and is particularly nasty sounding on cymbals and crash. The mouse activation of the Hydrogen mixer doesn't use any note-off, or none that I am aware of.

The "Ignore note-off" option in "Hydrogen Tools-Preferences-Midi System" is missed named, as it only helps ignoring zero velocity note-on midi messages. This option, if active, still passes "True" note-off commands which is what the Roland TD-9 uses too short after the hitting of a pad.

I was able to verify that the "Ignore note-off" option in the "Hydrogen Tools-Preferences-Midi System", stops zero velocity note-on messages, as this is the way a Yamaha DX-7 synthesizer kills released notes, and the option worked well on this keyboard, i.e. nice long cymbal sounds. In addition, the qmidiroute display showed the Yamaha DX-7 used zero velocity note-on midi messages and the Roland TD-9 uses note-off midi messages.


This mididings script in conjuction with Python not only stops zero velocity notes it also stops the midi note-off message. The cymbals and crash now sound as they should, when using the pads on the TD-9. When using this script of course the "Ignore note-off" option in the "Hydrogen Tools-Preferences-Midi System" has no effect.

I wonder if all those notes still playing, never being turned off, will eventually exceed some limit. If you are not using jackd then change the 'jack-rt' to 'alsa'. No guarantees implied, and I am not sure of the difference between the ~ invert and the - negation. Invocation is just from the terminal command line:

$ python

The "" script follows:

#   An attempt to stop note off midi messages from getting to Hydrogen
# from a Roland TD-9
# 4 Feb 2016							Alan Electron

from mididings import *


thijs's picture
Joined: 04/20/2010

or ...

you can goto Tools > Preferences > Midi system

and tick the 'ignore note-off' box