Coldplay's album X&Y features the single Speed of Sound. This is the follow up to their 2002 Brit and Grammy award winning A Rush of Blood to the Head. X&Y was recorded in 2004 at their studios in the UK and USA and has been produced by Danton Supple, Ken Nelson and the band. According to Chris (guitars, piano, vocals), In mathematics, X and Y were always the answers, but in life, no one knows. The album is about those unanswerable questions and what you should do about the fact that you can't explain all the unknown variables. The new massive, layered sound breaks new ground for Coldplay. The lyrics are about big issues like life and death, love and lost, fascination with the world around us but also about accepting that some things can never be fully understood.