Vocaloid is an advanced singing voice synthesis system developed by Yamaha that uses Frequency-Domain Singing Articulation Splicing and Shaping technology. This innovative approach allows for the creation of realistic vocal performances by manipulating various vocal elements collected from professional singers. These vocal elements, including phrases and expressive variations like vibrato, are stored in a specialized database after being converted into frequency domain data.

The system synthesizes vocals by retrieving voice snippets from the database and applying pitch conversion to match the melody specified by the user. By performing these processes in the frequency domain, Vocaloid achieves smooth and natural-sounding vocal transitions, enabling the seamless formation of words and phrases. This method ensures that the synthesized vocals maintain expressive nuances while adapting accurately to different musical contexts.

Vocaloid includes a comprehensive suite of tools such as a score editor for managing pitch, lyrics, and expression, along with the Vocal Sound Generator engine that produces the final vocal output. Each vocal library consists of pronunciation and timbre databases, which can be customized by recording real voices and capturing their unique vocal characteristics and variations. This system offers users the ability to create and modify vocal libraries to suit a wide range of musical styles and voices.