Revo is the composer, arranger, writer and producer of Sound Horizon, and its constant member.
He started composing during the 90's and uploaded his works in a website in which he signed as "G.Revo". The first album under the name of Sound Horizon was published in the Comiket 2001, and he was the only member.

He usually plays the guitar, and occasionaly piano, bagpipe and other instruments. Since Roman (2006) he also collaborates as a singer.

Since the "foundation" of Sound Horizon Kingdom, Revo has played the role of the king, so people refer to him as His majesty.

Jimang was the first male voice in Sound Horizon, when he joined in 2003 (Lost). He usually plays roles of old men (Such as as ABYSS in Elysion, Savant in Roman or Milos in Moira) due to his voice, and he is well known for his eccentric performances.

Besides singing, Jimang also acts as a seiyuu. He has released some albums and singles as a solo singer like the ED for the anime "Umineko no Naku Koro ni"

Aramary was the first singer in Sound Horizon. She started in 2002 with the 2nd Story "Thanatos" and left after the 4th Story "Elysion". She toke the leading role of the band during that period, and her voice became an icon of the doujin Sound Horizon.

She is well known for her narration (seiyuu) skills, being capable to imitate lots of different voices, like children, elderly and women.
After leaving Sound Horizon, Aramary joined the band Rain note and released an album and a single. She also works as a seiyuu for several doujin circle releases and TV spots.

KAORI (Kaori Oda) is one of the main singers from the second "era" of Sound Horizon. Before joining Sound Horizon, she was part of the vocal group CHIX CHICKS (formerly BJ GIRLS) which she left in 2008.

She is also part of Yuki Kajiura's FictionJunction project, and she has sung theme songs for several animes such as Baccano!, Tsubasa Chronicles or Pandora Hearts.

She has a strong deep voice, although she can also reach high pitches. Some roles she has taken in SH are Violette (Roman), Enjá (Seisen no Iberia), or Aioria (Moira)

YUUKI (Yoshida Yuuki) is one of the main singers from the second "era" of Sound Horizon. She was a Japanese Idol in 2003, when she was part of a Unit called SpringS. She also toke part in several TV Doramas in NHK and Fuji TV, as well as some commercials.

Her voice is high pitched and childish, well defined as a pop-commercial one. She as token some roles in SH such as Hortense (Roman), Layla (Seisen no Iberia) or Locria (Moira)

REMI is one of the main singers from the second "era" of Sound Horizon. She has made lots of "free collaborations" for animes like Naruto, GANTZ or Jigoku Shoujo.

She has a very special operatic voice, although very light and similar to a mezzo-soprano. Some roles she has played in SH are Rèine Michèle (Roman) Trin (Seisen no Iberia) and Myu (Moira)

RIKKI joined the band along with the other three vocalists, but her first collaboration with Sound Horizon was the Image Album LEVIATHAN, when Aramary was still in the band. She is a famous shimauta (traditional Okinawan music) singer, and is mainly know for having sung "Suteki da ne?" in FINAL FANTASY X. She gave birth to twins in 2008 and left the band during that year, but she returned in 2009.

Her voice is very high-pitched and influenced by traditional japanese singing. Some roles she has played in SH are "Mother" (Roman) or Saranda (Seisen no Iberia).