tonal spread (songwriting)

The tonal spread is difference between the high and low notes in a song. In general, the greater the spread of a song, the more emotional and interesting it is. Songs (or portions of songs) with a low tonal spread, tend to be monotone and uninteresting. This could also be called the "contrast" of the song, like the color contrast of a photo. In a photo, the brighter the colors are, the more appealing the photo is. In songs, this contrast is achieved through widely differing notes rather than colors.