The definition of the electro sound is the use of drum machines as the base of a track. A legendary drum machine with a recognizable sound still used today is the Roland TR-808. The instrumentation is generally all-electronic with a funk-style synthesizer bass line. Heavy use of effects such as reverb and echo together with electronic pads create a rich and simultaneously cold sound that emphasizes the common science fiction theme of the lyrics. Not all electro features rapping; vocals processed through a vocoder is a common element and instrumental tracks are more prominent than in related genres of electronic and hip hop music. In recent years it has become common for electro artists to perform using only laptop computers, this way emphasizing the technological theme of the music.
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