On Time Domain Conformer Models for Monaural Speech Separation in Noisy
  Reverberant Acoustic Environments
William Ravenscroft Stefan Goetze Thomas Hain
Speech separation remains an important topic for multi-speaker technology
researchers. Convolution augmented transformers (conformers) have performed
well for many speech processing tasks but have been under-researched for speech
separation. Most recent state-of-the-art (SOTA) separation models have been
time-domain audio separation networks (TasNets). A number of successful models
have made use of dual-path (DP) networks which sequentially process local and
global information. Time domain conformers (TD-Conformers) are an analogue of
the DP approach in that they also process local and global context sequentially
but have a different time complexity function. It is shown that for realistic
shorter signal lengths, conformers are more efficient when controlling for
feature dimension. Subsampling layers are proposed to further improve
computational efficiency. The best TD-Conformer achieves 14.6 dB and 21.2 dB
SISDR improvement on the WHAMR and WSJ0-2Mix benchmarks, respectively.