Trance is a style of electronic dance music that developed in the 1980s. Trance music is generally characterized by a tempo of between 130 and 160 BPM, featuring repeating melodic synthesizer phrases, and a musical form that builds up and down throughout a track. It often features crescendos and breakdowns. Sometimes vocals are also utilized. The style is arguably derived from a combination of largely electronic music such as ambient music, techno, and house. In the early 1980s, the German composer Klaus Schulze composed several albums of experimental, atmospheric space music.