what's the chance he simply took an ambient track and sped it up to 3.25 seconds? what's the chance he simply took an ambient track and sped it up to 3.25 seconds?Significant, I think.
Now, if he simply sped it up, the pitch would have gone into the ultra-sonic "dogs only" range. So if indeed he created it at the slow speed, when he shortened it he would have had to under-sample it and reconstruct it, to retain the proper pitches, while shortening only the time.
It's quite possible that's what he did. The beautiful complexity of the long version suggests to me that he did it that way.