Evaluating digital “on-line” background noise suppression: Clarifying television dialogue for older, hard-of-hearing viewers

Abstract

It is known that older people have disproportionately greater difficulties perceiving speech embedded in noise or otherwise degraded than do younger people. The Independent Television Commission (ITC) receives a number of complaints about programmes having excessive background “noise”. The Broadcasting Act 1990 gives the ITC responsibility for addressing the needs of elderly and disabled viewers of all independent television in the UK, and thus established a research consortium with the aim of reducing the impact of background noise. The findings presented in this paper are drawn from DICTION, a multi-disciplinary project partially funded by the DTI-LINK initiative, which has developed digital signal processing technology that identifies and suppresses the background noise of television programmes in real-time. A sample of elderly volunteers (63–84 years) underwent pure tone audiometry and provided data based on objective tests of intelligibility per se, and on their subjective impressions of the auditory material (e.g., clarity of dialogue, intrusiveness of background noise, etc.). The findings illustrate the effects of age and hearing loss and the dissociation of objective and subjective measures. They also show that under certain noise conditions clear-cut improvements in intelligibility are beyond current signal processing techniques although apparent improvements in clarity (etc.) are not.