He's a new sub-species of human which i call 'Homopotamos Irregularis'. A wily creature, he can usually be found at carnivals and festivals in southern USA. The distinguishing features of a wicker boater, unkempt facial hair and beady, bloodshot eyes are often mistaken for the characteristics of a down-and-out. Be wary though, his amiable appearance conceals extremely strong jaw muscles which have been known to strip the flesh from the arms of unwary Homosapiens who attempted to steal his chargrilled chicken.
Anyhoo, back to the music. I feel that the best way to make the background music more random (apart from maybe during battles) is to have a large selection of short audio clips (1-2 minutes in length each). At a randomly selected time, say every minute or so, the game should choose a randomly selected clip (which is specific to that race) and fade it in slowly (maybe over the space of 15-30 seconds) while the existing audio clips continue to play. As a clip nears it's end, the game should fade it out slowly, again over 15-30 seconds or so. Modulation of volume and panning for each track could also be applied.
By taking all of the random factors into account ...
1. which clip should start playing next
2. when the clip should start to play
3. how long it fades in and out for
4. modulation of the volume and panning of the clip while it is playing
... we will get a constantly changing and unique melange of audio ambience which will never sound the same at any 2 points in time. This will hopefully stop the music from becoming something which people hate listening to and eventually turn off altogether. It would be necessary to make sure that the audio tracks for each race are written in a minimalistic style and with little or no percussion or repetitive elements such as drumbeats, since these would not mix together well in a randomly generated soundscape such as the one i am suggesting. The minimalistic style of writing for these tracks would also be necessary to ensure that if 3 or 4 tracks are overlapping each other, you don't end up with an over-the-top mess of noise, but as long as some thought is put into the production of the audio tracks, that shouldn't be a problem.
Ideas for the audio of specific races could also be interesting to create. e.g. an underwater race could have lots of muted bubbly noises; a space-based race could have lots of higher-frequency pulses and well-constructed noise to represent the energy emitted by stars, gas-giants, black-holes etc; a flora/fauna race could have the sounds of wind rushing through trees and plants rubbing together.
I could also write some pseudo code to govern control of the audio tracks if anyone is interested in using these ideas. I'm reasonably experienced at HTML, MySQL and especially Flash Actionscript where i have used random generation of this type for graphics and audio in previous projects of my own. I'd also produce some audio tracks to test it out with. Once everyone was happy with the code and test audio and how it all worked together, it would just be a case of getting a decision on the final race-types and coming up with themes for each race and then producing the audio for them.
Any thoughts people have on these ideas would be appreciated.