"Speed of Sound" is a song by British alternative rock band Coldplay. It was written by all members of the band for their third studio album, X&Y (2005). Built around a piano riff, the song builds into a huge, synthesiser-heavy chorus. It was released by Parlophone Records as the lead single from the album. "Speed of Sound" was released in the US on 18 April 2005, and then made its radio premiere on BBC Radio 1 with Lamacq on the day of the release on 19 April. The single was pressed with two B-sides: "Things I Don't Understand" and "Proof". The song premiered in the UK on 23 May.
Coldplay vocalist Chris Martin admitted that the song was developed after the band had listened to English art rock singer Kate Bush. The song's drum beat is similar to Bush's 1985 song "Running Up That Hill". Upon the song's release, it charted in the UK Singles Chart in the number two position. In the United States, it debuted at number eight on the Billboard Hot 100, their first top ten hit in the country, and their most successful song until "Viva la Vida" reached number one in 2008.