There is lot of difference between listening music and screeching sound of fingernails on chalkboard. Difference could be seen on the face of listener, level of irritation gets raised when one hears screeching of fingernails, but feeling of relaxation comes when hears music.

Researcher Michael Oehler from University of Cologne in Germany has tried to present an explanation for this situation. He said in case of certain sounds, like sound of fingernails or chalk scraping on a chalkboard gets amplified inn such a way that irritation level of that sound gets elevated.

Increased level of irritation could lead to stress and the level would rise with increase in the rate of sound. Michael, who is also professor of media and music management, was of the view that screeching sound strikes the ear at maximum frequency, between 2000 and 4000 hertz.

This level is quite high for human ear, and to avoid the sound, the ear canal works in a particular manner which rather than reducing the frequency, enhances the sound even more. One solution, which was devised by Oehler, was that pitch of the sound should be reduced and then the sound disturbance could sound bearable.

He knows pitch should be reduced but to what level, he has no idea and would require further research in that regard. The study would be presented at the annual meeting of the Acoustical Society of America, which would take place in San Diego, this week.

One of the important things that have been mentioned in this research is `perception'. Attitudes do matter, and to prove that he conducted an experiment, in which he recorded the sound of chalk scratching on the board and asked people to listen it.

Difference was that one group was told that it is contemporary music and other group was told that it screeching of chalk on the board. Pleasantness was more in the case of group, who listened to it as music.