Each track is assigned a sound effect ID. This is the sound that is used to playback the note based on the given note and octave. When you create a new project or use one of the templates, the first four sound effects are already set to musical instruments: melody, harmony, bass, and drums. Each track is assigned to one of these instrument IDs. This allows you to start making music without having to set up any of the tracks by hand. You can also modify the number of tracks in the
data.json file or with the help of the Chip Editor Tool. Some of the templates such as the GBoy System only have 3 track available.
If a track is unavailable, it will be grayed out. It is important to note that each track corresponds to a giving audio channel. That means if you are playing a pattern that uses all 4 tracks, and a sound effect is played on one of the channels, the music note will be ignored until the sound effect is done playing. If the sound effect is longer than a single note, the tracker may try to change the note value of the sound effect which could have some strange side effects.
It is best to leave a single channel open just for sound effects or limit the length of sound effects so they don’t bleed over into the next note of the tracker. So if your game has 4 channels, you can reserve the last channel for sound effects. The Music Tool can only edit 4 tracks so you can manually change the track total in the data.json file to add an additional channel dedicated to sound effects as well. It is up to you and how faithful to a system’s specs you want to stay.