As of Unity 3.0, we are proud to give our users the possibility to use Module files for music and sound in their productions just as any other audio asset.
When I started testing Unity's new audio features I had very little idea about what Module files are and what they could do. I asked our audio programmer, Søren, what it was and what I should look for, he replied that it is this tiny file format that allows for cool sound quality - "Just try it out". And I must say, comparing the file size to the audio quality, I was amazed, thinking that this will impact online and mobile gaming experiences in a good way.
Tracker Modules are best known from the demo scene's composers and the good old Amiga games' sound tracks and I must admit that it brought memories from late nights playing my brother's Amiga. The format can be described as being somewhere in between the well known, but declining, MIDI format and the concurrent PCM formats (including .aiff, .wav, .ogg, and .mp3).
The power of the Module files lies in the fact that they consist of high quality PCM samples that ensure a similar experience on all hardware. The files then contain additional info about when to play the sound, at what pitch, volume, effect, etc. This is where MIDI's shortcomings are evident: MIDI sounds are normally dependent on the sound bank that are in the hardware that outputs the sound. Unity supports four major Module file formats: Impulse Tracker (.it), Scream Tracker (.s3m), Extended Module File Format (.xm), and the original Module File Format (.mod).
Why not use compressed PCM audio, you say. You can always do that if size and bandwidth are plenty, but if you want a fair sound quality you will still end up using around 1 mb of disk space per minute. Using a mod file you can use and reuse the same samples embedded in the file over and over again. A skilled tracker artist can create hours of high quality audio for 1 mb worth of samples, provided using the right tricks.
There is a substantial amount of artists creating music using Trackers. As mentioned, the majority have been making soundtracks on the demo scene for the past 20+ years. Many of these artists publish their music through net labels such as Monotonic, SLSK Records, and Bump Foot. It is also worth mentioning that these labels and artists often release under Creative Commons licenses, which mostly means that it can be used, remixed, and redistributed as long as the artist gets credits. A great way to get assets for indie developers - just remember to pay them if you earn money on their work ;-). Kudos to the artists for democratising their expressions this way.
Module files can be created using tracker software. Conceptually trackers work slightly different from conventional software sequencers such as Prologic, GarageBand, Cubase, etc. I encourage you to take a look at some trackers if you are making music. There are many free and open source trackers. Among these I can recommend the cross-platform MilkyTracker or OpenMPT if you sit on Windows.
Happy tracking! I am looking forward to see how you'll use this feature.