  When we place microphones close to a sound source near other sources in audio
recording, the obtained audio signal includes undesired sound from the other
sources, which is often called cross-talk or bleeding sound. For many audio
applications including onstage sound reinforcement and sound editing after a
live performance, it is important to reduce the bleeding sound in each recorded
signal. However, since microphones are spatially apart from each other in this
situation, typical phase-aware blind source separation (BSS) methods cannot be
used. We propose a phase-insensitive method for blind bleeding-sound reduction.
This method is based on time-channel nonnegative matrix factorization, which is
a BSS method using only amplitude spectrograms. With the proposed method, we
introduce the gamma-distribution-based prior for leakage levels of bleeding
sounds. Its optimization can be interpreted as maximum a posteriori estimation.
The experimental results of music bleeding-sound reduction indicate that the
proposed method is more effective for bleeding-sound reduction of music signals
compared with other BSS methods.
