  In this paper, we first provide a review of the state-of-the-art emotional
voice conversion research, and the existing emotional speech databases. We then
motivate the development of a novel emotional speech database (ESD) that
addresses the increasing research need. With this paper, the ESD database is
now made available to the research community. The ESD database consists of 350
parallel utterances spoken by 10 native English and 10 native Chinese speakers
and covers 5 emotion categories (neutral, happy, angry, sad and surprise). More
than 29 hours of speech data were recorded in a controlled acoustic
environment. The database is suitable for multi-speaker and cross-lingual
emotional voice conversion studies. As case studies, we implement several
state-of-the-art emotional voice conversion systems on the ESD database. This
paper provides a reference study on ESD in conjunction with its release.
