Masker design for real-time informational masking with mitigated annoyance

Abstract

An alternative design of masker for real-time speech masking is proposed. Time-reversed speech, which is also adopted in the proposed design, has been commonly used for speech masking because of its efficient performance in making the target speech unintelligible using informational masking. However, previous studies revealed that a time-reversed speech causes more annoyance and cognitive distraction for the listeners. Meanwhile, although generating time-reversed speech from the target speech would help improve masking effectiveness, it would require real-time processing as the target speech would not be available beforehand. The proposed masker design utilises techniques known for minimising discontinuities in the waveform of synthesised speech in order to minimise annoyance and distraction to the listeners. The design also avoids processes that hinders real-time generation of the masker. Results of subjective listening tests reveal that the proposed design is able to compromise the level of annoyance and the masking effect. Only marginal improvement is observed in the level of distraction. Further attempt to mitigate annoyance of the proposed masker by adding artificial reverberation did not help as it also reduces the masking effect significantly.