Modulation (changing the key of a song, or changing where the "home" note is) is a technique used in many, many forms of music. Some musicals go up a half-step every 8 bars, some pieces have the same harmony for hours on end. The particular kind of modulation that I did in this next clip is not very common: down a half step. I'm not sure why, but it came to me pretty naturally in this song. Here are two clips to compare: one from the beginning of the track, so you can hear what key I started in, and the second with the climax and part of the outro of the song, to hear where I went. Enjoy! (and of course, there are more French horns in this clip!)