"Spectrum" is a song by popular dance/pop producer Zedd, originally sung by Matthew Koma.
kz, the sole member of livetune, called himself a fan of Zedd on social media site Twitter. This spurred Universal Media Japan to ask livetune to create a remix. Zedd was impressed with the final result, and decided to include on the Japanese release of his album Clarity. The track features Hatsune Miku singing in English, with tuning by Circus-P.
The original short version of the remix, featured backing vocals by Matthew Koma, was uploaded to YouTube but later made private. Another short version was uploaded on February 7, 2013, with the backing vocals removed. Universal Music Japan uploaded the full version to its YouTube channel on February 25. An extended mix was played at Voca Nico Night in summer 2013 during kz's session as DJ.