Adding on Anthony's comment.. a "Tracker" usually refers to software that bundles into a single file waveforms for custom instruments and sequences of note data to be played on those instruments. Those were rarely (ever?) used in old console games, but were used frequently for older computer games.

I used to use a custom-written sound system for Genesis/Megadrive (as well as arcade and SNES) that used text files containing lists of notes. I'd have a separate list for each instrument, and each track woudl look kind of like this

Song1Track1

patch FMBass2

volume 10

loop 8

note E3,30 // play an E 8th note

endloop

note fs3,30

note g3,30

note b3,120 // b half note

...etc, etc.

I would generally compose using paper and pencil on music paper, and then enter the notelists in. I probably did around 30-40 console games using this system, and maybe 50 arcade games with it.

Other Genesis composers I knew used similar systems.

There were other MIDI-based systems (such as GEMS, which was tool developed by Sega), which some people used as well.

Genesis/Megadrive had enough channels that most games generally didn't have to rely on the "play one line and make it sound like 2" technique. That was a lot more common in NES or GameGear games, which had far fewer channels. In that case we would sometimes write the melody and bass using the same "track", using short notes (like a Bach violin partita)

My project is mainly about polyphony and I would like to remark upon the fact that tracker music usually consisted of monophonic melody lines that when played together may appear to be polyphonic. This is the exact point I need some reference material for. I only 'know' this currently because I have acquired Renoise tracker files for Sonic music that have been fan made, and I can only assume...

Mod based files (created by Trackers) were used for Atari ST and Amiga games.

They were also used in early PC games when space was tight.

See example:

• Star_Control_II
• Jazz_Jackrabbit_2 (check out who the composer is).
• Deus_Ex (this guy is everywhere... *wink*)

Something that you might find interesting if discussing polyphony is:

1. The concept of virtual polyphony vs real polyphony:

In general midi you are restricted by real polyphony. 1 note, 1 midi instrument sound.

In a mod, you are still restricted 1 note, 1 sound. However within that sound may be more complex sounds - such as guitar chords, drum tracks or layered (kick + hat) , choir riffs and even multi-instruments layered into a single note. Used to use these tricks to create more than 4 channel sounds on old .mod files.

2 . Simulated polyphony:

a. Fast arpeggio notes as in in chip music give the illusion of chords and trick the ear into hearing more polyphony than there actually is.

b. Interspersed notes in the channel - this technique we used to use to make it sound like a note that was cut off by another sample playing was continuing, echoing or reverb but placing the samples between other shorter samples.

That being said - trackers are just tools - I've used trackers to create midi for mobile phone games, I've used trackers also to create rendered music for games.

Something that you might find interesting is the concept of virtual polyphony vs real polyphony.

If you're looking for an 'academic' reference, I presented a paper on creating arcade music (which used the same technology as the Sega Genesis/Megadrive) at the International Computer Music Conference back in 1989..

http://quod.lib.umich.edu/i/icmc/bbp2372.1989.066/1/--designing-sound-tracks-for-coin-op-games-or-computer-music?page=root;size=150;view=image

Game audio researcher Dr. Karen Collins has also published a lot of scholarly articles on a lot of aspects of game music.

I also did some asking around from some fellow 'old school' game composers-non that I talked to used "Trackers" for Genesis/Megadrive music. So although we used systems that were "like trackers" in some ways, we didn't use actual trackers.

Hope that all helps!

Those were rarely (ever?) used in old console games

Tracker music have found it's place on consoles in the late nineties and later. Especially on consoles with very limited capabilities like GB, GBA, NDS and so on. For example Paragon 5 tracker was dedicated to create music playable on Gameboy console:

Later more tools developed, including Echo Sound Engine for Sega Mega Drive: http://segaretro.org/Echo

But at the times it would be to much hassle for consoles to play multichannel tracker files. I can't recall such use back then. I believe there were non or not significant amount of trackers usage.