External websites we've worked on: Dr Andy Moorhouse on piano ... Prof Trevor Cox
Improving Television Sound for the Hard of Hearing
ITC "CLEAN AUDIO" PROJECT
This research was carried out during the period April to September 2003 at the Acoustics Research Centre in the University of Salford. The Clean Audio Project is funded by the Independent Television Commission (ITC)
The project looks at the effect that different audio reproduction methods have on the enjoyment, perceived sound quality and the dialogue clarity of television audio for hard of hearing viewers. This was then compared with the effect on non-hearing impaired viewers.
The ITC receive many complaints from hard of hearing viewers saying that the background sound or music is too loud and makes it difficult to understand the dialogue. Dolby Digital 5.1 contains a number of discrete audio channels one of which (the centre channel) is a dedicated dialogue channel. This allows us to adjust the level of left and right speakers in relation to the centre speaker so that the music and background sounds have been reduced in relation to the dialogue.
A series of listening tests were carried out using different audio reproduction methods. Subjects were asked to compare these processes based on dialogue clarity, overall sound quality, and their enjoyment of the clip.
An additional test involved subjects to set their own percieved comfortable listening level for each process.
Key to processes assessed:
- LCR Centre channel, plus left and right channels at standard relative levels set using reference tones.
- LCR1 Centre channel, plus left and right channel at -3dB.
- LCR2 Centre channel, plus left and right channel at -6dB.
- C Centre channel only.