http://www.bbc.co.uk/complaints/issue/2008/06/080626_issue_background_sound.shtm...Updated 6th July 2010.
For interest.
Background sound
The use of background music or sound in programmes is often too intrusive and irritating.
We appreciate that some viewers and listeners are irritated by music or background noise in programmes. Some find noise makes it difficult to hear dialogue, while music may be considered badly chosen or even unnecessary. Naturally we regret this whenever it causes annoyance or frustration.
It is difficult to strike the right balance between differing opinions on acceptable levels of noise and music. Music in particular is partly a subjective matter in which personal taste plays a large part. It is added to programmes for many reasons and can be vital to underpinning moods and feelings, adding dimensions to a programme or conveying emotion. It has many applications in programme making.
Programmes can often sound different in the editing suite compared with being viewed on an ordinary television set. And although producers can control these effects within the programmes they make themselves, other programmes are bought in and there is no straightforward way to vary background sound levels before broadcast.
Many televisions now have options whereby audio settings can be changed to a personal preference setting, or amended to suit the type of programme being viewed. There is usually a default setting for "music" or "speech" meaning that viewers may be able to adjust their television's sound to make speech clearer. Similarly, viewers with surround sound systems may be able to clarify speech by increasing the volume on the centre (dialogue) speaker whilst decreasing the volume on the surrounding channels (music and effects).
Nevertheless, the BBC already has detailed guidance for producers to assist them in their decision-making when it comes to the audibility of a programme. This guidance has been devised in consultation with RNID and the National Deaf Children's Society and is available to all BBC staff through the BBC's intranet. The BBC is also undertaking a research project about television intelligibility which goes beyond investigating the problems with background music. This is because viewers have identified a number of issues, apart from music, that can impact on their ability to understand what is being said. The BBC is collaborating with several organisations, including RNID, who are conducting their own research into this issue. The BBC and RNID will coordinate the research and share the findings.