The ambient music at Walt Disney World is the result of a highly refined system put in place to correct a problem nobody ever noticed.
In the mid 1990’s, the park started researching the problem. It would eventually find no existing solution, so the engineers had to design and construct, on their own, one of the most complex and advanced audio systems ever built. The work paid off: today, as you walk through Disney World, the volume of the ambient music does not change. Ever. More than 15,000 speakers have been positioned using complex algorithms to ensure that the sound plays within a range of just a couple decibels throughout the entire park. It is quite a technical feat acoustically, electrically, and mathematically.
Incredible attention to detail to ensure that the visitor experience is as perfect as possible.
(via boing boing)