  In this study, we define the identity of the singer with two independent
concepts - timbre and singing style - and propose a multi-singer singing
synthesis system that can model them separately. To this end, we extend our
single-singer model into a multi-singer model in the following ways: first, we
design a singer identity encoder that can adequately reflect the identity of a
singer. Second, we use encoded singer identity to condition the two independent
decoders that model timbre and singing style, respectively. Through a user
study with the listening tests, we experimentally verify that the proposed
framework is capable of generating a natural singing voice of high quality
while independently controlling the timbre and singing style. Also, by using
the method of changing singing styles while fixing the timbre, we suggest that
our proposed network can produce a more expressive singing voice.
