  Recently, deep clustering (DPCL) based speaker-independent speech separation
has drawn much attention, since it needs little speaker prior information.
However, it still has much room of improvement, particularly in reverberant
environments. If the training and test environments mismatch which is a common
case, the embedding vectors produced by DPCL may contain much noise and many
small variations. To deal with the problem, we propose a variant of DPCL, named
DPCL++, by applying a recent unsupervised deep learning method---multilayer
bootstrap networks(MBN)---to further reduce the noise and small variations of
the embedding vectors in an unsupervised way in the test stage, which
fascinates k-means to produce a good result. MBN builds a gradually narrowed
network from bottom-up via a stack of k-centroids clustering ensembles, where
the k-centroids clusterings are trained independently by random sampling and
one-nearest-neighbor optimization. To further improve the robustness of DPCL++
in reverberant environments, we take spatial features as part of its input.
Experimental results demonstrate the effectiveness of the proposed method.
