  We construct a corpus of Japanese a cappella vocal ensembles (jaCappella
corpus) for vocal ensemble separation and synthesis. It consists of 35
copyright-cleared vocal ensemble songs and their audio recordings of individual
voice parts. These songs were arranged from out-of-copyright Japanese
children's songs and have six voice parts (lead vocal, soprano, alto, tenor,
bass, and vocal percussion). They are divided into seven subsets, each of which
features typical characteristics of a music genre such as jazz and enka. The
variety in genre and voice part match vocal ensembles recently widespread in
social media services such as YouTube, although the main targets of
conventional vocal ensemble datasets are choral singing made up of soprano,
alto, tenor, and bass. Experimental evaluation demonstrates that our corpus is
a challenging resource for vocal ensemble separation. Our corpus is available
on our project page (https://tomohikonakamura.github.io/jaCappella_corpus/).
