Midi Configuration

JJazzLab is a Midi-based application. It does not directly generate audio output, rather it generates Midi messages (eg “play a D on the bass”) which are sent to a sound device via a Midi connection.


Midi config image

The key things to check are:

  • The selected JJazzLab Midi Out device (menu Tools/Options/Midi) is connected to your sound device.
  • Your sound device is in multitimbral mode : different instruments can be played on different channels.
  • Your sound device is in General Midi (GM) mode : standard GM instruments can be selected by JJazzLab.

Note that you can use JJazzLab even if your sound device is not GM-compatible, see below.

Midi Configuration Wizard

This wizard will help you select the JJazzLab Midi out device and configure your sound device.

It is launched automatically the first time you run JJazzLab. You can also run it manually from the menu Tools/Midi Configuration Wizard.

Using a non GM-compatible sound device

JJazzLab rhythms define a default GM instrument for each of the rhythm tracks. For example the “Swing” rhythm could define the GM sound “Acoustic bass” (program change=33) as the default instrument for the bass track on channel 11. This helps achieving a consistent rendering on GM compatible sound devices.

If your sound device is not GM compatible, JJazzLab won’t be able to automatically select the appropriate sound.

You have 2 options:

Manually configure your sound device

On your sound device set the appropriate sound for each channel used by the JJazzLab rhythm. For example select an acoustic bass sound on channel 11. In the mix console you might want to set the JJazzLab instrument on channel 11 to “!NotSet!” or disable the Instrument midi messages in the channel settings, so that JJazzLab does not send any program selection Midi message which could change your device configuration.

Provide a Midi Synth definition file for your sound device

This is the recommended option when it’s possible. The Midi Synth definition file tells JJazzLab how to access your sound set. For example you will be able to assign, directly from the Mix Console, an acoustic bass sound for the bass rhythm track. See Instruments Configuration for more information.

Drums issues with GM-compatible sound devices

A GM-compatible sound device accepts drums/percussion data only on channel 10. What if the JJazzLab song needs more than one drums channel ?

This typically happens for rhythms which have a drums track on channel 10 and another drums track for percussion (say channel 9). This also happens if a song uses 2 different rhythms.

The consequence is that when you play the song you hear strange repetitive sounds. For example because JJazzLab sends percussion data on channel 9 while the sound engine has a piano sound on channel 9.

So what can be done ?

Provide a Midi Synth definition file for your sound device

This is the recommended option when it’s possible. Many sound devices actually allow to select a drums instruments on any Midi channel. But JJazzLab must know the specific Midi messages required to do this. This is done by providing a Midi Synth definition file for your sound device. Then you can set the Default Drums and Percussion instruments with a drums sound from your device. See Instruments Configuration for more information.

GM2-compatible sound device

GM2 extends the GM standard with new capabilities. One of them is the possibility to select drums instruments on any channel. If your instrument is GM2-compatible, you should define the Default Drums and Percussion instruments with a GM2 drums sound. See Instruments Configuration for more information.

Enable the Drums rerouting option

JJazzLab can reroute non channel-10 drums/percussion tracks to channel 10. JJazzLab will automatically propose to activate this option upon playback if it detects a potential problem. The option can also be manually activated in the settings dialog of each drums-type channel in the Mix Console (see image below). Channel settings