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. That’s why JJazzLab needs to know about your Midi configuration in order to work properly.
In general we recommend to use the JJazzLab SoundFont.
If you’re familiar with Midi and use a hardware synthesizer or VST/AU instruments, then learn about the Output Synth Editor.
Midi Configuration Wizard
This wizard will help you select the best Midi configuration.
It is launched automatically the first time you run JJazzLab. You can also run it manually from the menu Tools/Midi Configuration Wizard.
Drums issues with GM-only compatible sound devices
A GM-only compatible sound device normally 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 drum track on channel 10 and another percussion track (say channel 9). This also happens if a song uses 2 different rhythms. Note that this should never happen if you use the JJazzLab SoundFont.
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 ?
- If your synth can handle several drum channels, use the Output Synth Editor to tell JJazzLab how to use this capability
- 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).