The voice of female vocalist Hatsune Miku has become the talk of Japan's Internet community. Her voice is husky with just a hint of sweetness, and she has the spellbinding appearance of an anime character. Hatsune Miku is certainly no ordinary girl. In fact, she is no girl at all. Hatsune Miku is a synthesized voice, a virtual singer, and the name of a new speech synthesis software application that was developed and is now being marketed by a software manufacturer.

Hatsune Miku on DVD. (C)Crypton Future Media, Inc.

The Hatsune Miku anime character. (C)Crypton Future Media, Inc.

What Makes Hatsune Miku Sing?
Hatsune Miku's voice is produced by a dedicated voice generator using a voice synthesis engine called Vocaloid 2. The Vocaloid 2 engine, developed by music industry manufacturer Yamaha, is based on an audio library composed of vocal song recordings of voice actress Fujita Saki performing as an animation character.

The name of the voice synthesis engine, Vocaloid, was coined by combining the words "vocal" and "android." Vocaloid functions using a technology developed by Yamaha known as Frequency-domain Singing Articulation Splicing and Shaping. This technology connects vowels and consonants in voice data to produce smooth speech.

Before Vocaloid 2, other voice synthesis software packages on the market used the original Vocaloid voice synthesis engine. Then, in August 2007 the Hatsune Miku application went on sale based on the new Vocaloid 2 voice synthesis engine boasting more natural-sounding vocalizations.

In the new software release, an imaginary pop-star-of-the-future image was conceived for Hatsune Miku, and an animated depiction of the pop starlet was created to complement her unique synthesized voice. Her adorable appearance provides amateur music producers with a sense of her physical presence to match her captivating voice. Users of the software can then better visualize what kind of voice Hatsune Miku has and in what style she would be likely to sing, helping them to produce intriguing music. The combination of Hatsune Miku's synthesized voice and image has produced a mega-hit in desktop music-software terms, selling more than 15,000 units within two months of its initial release.

What Lies Behind Hatsune Miku’s Popularity?
The popularity of Hatsune Miku was first bolstered when would-be producers began posting files of songs they had created using the software on video-sharing websites. This initial popularity generated requests for more postings, and before long many people who had previously been uninterested in desktop music found themselves drawn to Hatsune Miku.

A screenshot of the Hatsune Miku application. (C)Crypton Future Media, Inc.

Speech synthesis technology continues to improve with fine adjustments continually being made to the technology, bringing it ever closer to sounding like real human song. The efforts put into making this technology a success may have been motivated by the dream many people have of producing songs for a popular singer. The peculiarities of synthesized speech and the Hatsune Miku anime character are certainly part of this software's widespread appeal.

Most of the songs initially released using Hatsune Miku were existing popular titles. Gradually, though, the original intent of Hatsune Miku is being realized as fresher and more inventive songs are produced. One such song that has been particularly well received is called "Miku Miku ni shite ageru" (I'll Be Miku Miku For You), which is being transmitted through the Joysound network of karaoke outlets.

A Hatsune Miku doll and other products have also been launched. Hatsune Miku even hosts the beginning and ending portions of NHK Television's program The Net Star, which highlights content that is available over the Internet.

Hatsune Miku has certainly come a long way. Now the question is whether this rising talent, with her trendy pop star persona and computerized sound, will develop a full-fledged professional singing voice so realistic that she could actually be mistaken for a living and breathing human vocalist.