Somebody in a forum and others privately expressed their appreciation of the game music. I thought that the technical details might be interesting to everybody, so...
Right from the start, I wanted:
* the game to run on stock machines;
* the game to run at 50 fps;
* music and sound effects to play at the same time, without music instruments being cancelled by sound effects;
* the music to change dynamically depending on the game situation;
* the game to fit on a single floppy disk;
* to have everything load at boot and thus avoid loading while playing.
The unusual route I took was the easiest on the hardware: pre-recording the music as various sound samples to play on 2 of the 4 Paula channels, thus leaving 2 channels free for the sound effects.
This allowed the music to be made of virtually infinite channels. Therefore, I went for 8 channels: 2 for drums (I could have used more to be honest, but, really, it would have hardly made much difference), 1 for bass, 1 for strings and 4 for the melody synth (given that the instrument echoes, it needed space). Of course, more notes and more instruments could have been added, but that would have made the music too intrusive, whereas I wanted it to be just a background accompaniment.
Here is the "normal" music (i.e. the music that plays when no bonuses or maluses are active):
https://www.youtube.com/watch?v=eNRSgg_GnWIThe downside of this choice is that the samples take a lot of space - especially considering that I went for a rather high quality: 28604 Hz. As a consequence, the music is mono (this halves the amount of data) and shortish (each tune lasts only a few seconds). The fact that music is mono is hardly a problem: since it is just a background accompaniment, the subtleties of stereo are not that important. The fact that the 5 tunes that the music is comprised of are short is counterbalanced by their frequent switching from one to another due to what happens while playing.
In the end, the music ended up taking 1304526 bytes (i.e. almost 1.25 MB), for a total duration of 45.6 seconds. Such size was the limit to leave enough CHIP RAM for the rest and to have the data fit on the floppy disk.
By the way, to actually get the game to fit on a floppy disk, I had to compressed the tunes. Luckily, I had some methods and tools ready, as I had originally developed them for SkillGrid (that game also uses pre-recorded music, although it is stereo and decompressed in real time): I just had to choose those that would produce the best results and write the unpacker routine that would decompress the data at startup (unfortunately, I did not have it for the method that produced the highest compression ratio). Compressed, the music amounts to 622067 bytes (about 52.3% compression ratio).
Side note: I used the same compression method also for the other tunes (which are combined toghether into a regular tracker module) and the sound effects.
