Musical additions sound alarm

A piece of music can be spare -- containing only one or a few musical lines played by different instruments, or can have a larger range of parts that make up a rich background of harmony.

Researchers from the University of Munich and Saarland University in Germany are using music to convey information depending on whether a particular part is present or absent in an overall composition. The researcher's prototype uses music composed so that particular parts can be added or subtracted without losing the aesthetic quality of the piece as a whole.

This makes it possible to convey information like an alert to particular people that will go unnoticed by others.

The idea takes advantage of the way the mind perceives its environment. Background music is usually perceived only peripherally. When a tune that is especially liked or disliked comes on, however, it tends to cross into conscious perception. When someone has chosen a particular instrument or musical phrase as a notification, that person will become aware of the music when it plays.

The method to be used, for example, with the ambient music present in public places like shopping malls to notify security personnel without disturbing anyone else, according to the researchers.

The researchers have developed a prototype with eight directional speakers that is designed for a user study. Notification can be given using a particular phrase or instrument and can also be given from specific directions.

One of the researchers' demonstration compositions includes core cello, keyboard, violin and drum parts, and an optional piano part that fits into the rest of the music but moves a little faster.

The method is ready for practical use now. They presented the research at the Intelligent User Interfaces Conference (IUI 2005) held January 9 to 12, 2005 in San Diego.