The earliest known development related to Vocaloid was a project that had occurred two years prior and funded by Yamaha.

The project was codenamed "Elvis" and did not become a product because of the scale of its vocal building required for just a single song.

[4] The first Vocaloids, Leon and Lola, were released by the studio Zero-G on March 3, 2004, both of which were sold as a "Virtual Soul Vocalist".

[5] Leon and Lola were also demonstrated at the Zero-G Limited booth during Wired Nextfest and won the 2005 Electronic Musician Editor's Choice Award.

Later that year, Crypton Future Media also released the first Japanese Vocaloid Meiko who, along with Kaito, was developed by Yamaha.

[13] Lola was noted for her deep tone that left her sounding "like Big Ma", but was generally considered the better of the two Soul singers.

Nothing is known about her voice provider except she was a black singer who was established in Great Britain, whose roots were noted back in the Caribbean.

[4][17] A complementary male vocal for Meiko, Kaito was released on February 17, 2006 for the Japanese version of the software.

[4] Kaito was initially acknowledged as a commercial failure and sold poorly, bringing in only 500 units in contrast to Meiko's 3,000.

His lack of sales in contrast to Meiko was put down to the reader demographic of DTM magazine, which 80% were male.

[19] Sales picked up suddenly in 2008 to the surprise of Wataru Sasaki and other members of Crypton Future Media and by 2010 had over taken Meiko in popularity.

[22] At the time of its release, Popular Science reported that, "Synthetic vocals have never even come close to fooling the ear, and outside of certain Kraftwerk chestnuts, robo-crooning is offputting."