Interesting layered approach to music in online multiplayer games:
"The human mind is designed to recognize recurring patterns. This is how we learn to identify things in the world -- through our senses in an organised pattern: Recurring sounds, visuals, smells etc. Unfortunately, recurring musical patterns - otherwise known as loops - start to get annoying after a while, especially if they go on and on and on. Even though the music doesn't draw any attention to itself, the pattern that it is repeating will ... Our solution to this problem was to create a tool that allowed us to combine many small samples of music into a continuous track ... It allowed us to create a single track built up of many smaller pieces which were combined on the fly to create an ever-changing soundtrack."
Gamasutra: The Music of Anarchy Online: Creating Music for MMOGs
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