Shrillness is a word used to describe the quality of sounds that have a high-pitched, strident, raucous, screeching or harsh character, such as those produced by a

trumpet The trumpet is a brass instrument commonly used in classical and jazz ensembles. The trumpet group ranges from the piccolo trumpet—with the highest register in the brass family—to the bass trumpet, pitched one octave below the standard ...

piccolo The piccolo ( ; Italian for 'small') is a half-size flute and a member of the woodwind family of musical instruments. Sometimes referred to as a "baby flute" the modern piccolo has similar fingerings as the standard transverse flute, but the so ...

, but it can also be used to describe a widely recognised and puzzling phenomenon whereby certain sounds are perceived as psychologically painful or aversive to a degree that cannot be accounted for simply in terms of

frequency Frequency is the number of occurrences of a repeating event per unit of time. It is also occasionally referred to as ''temporal frequency'' for clarity, and is distinct from ''angular frequency''. Frequency is measured in hertz (Hz) which is eq ...

content or

loudness In acoustics, loudness is the subjectivity, subjective perception of sound pressure. More formally, it is defined as, "That attribute of auditory sensation in terms of which sounds can be ordered on a scale extending from quiet to loud". The rel ...

. Such sounds include the sound of fingernails scraping a chalkboard, the sound of chalk on a blackboard, the sound of glass being scratched, and possibly the sound of a baby crying. There have been attempts to explain the phenomenon, often in terms of frequency content, or evolutionary advantage, but so far no complete explanation or mechanism has been found.

Research

A 2011 study by

musicologist Musicology (from Greek μουσική ''mousikē'' 'music' and -λογια ''-logia'', 'domain of study') is the scholarly analysis and research-based study of music. Musicology departments traditionally belong to the humanities, although some mu ...

s Michael Oehler and

Christoph Reuter Christoph Reuter (born 28 November 1968) is a German University professor for systematic musicology at the University of Vienna. life Born in Duisburg, Reuter studied musicology at the University of Cologne, received his doctorate ''summa cum ...

has led its authors to hypothesize that the unpleasantness of the sound is caused by

acoustic resonance Acoustic resonance is a phenomenon in which an acoustic system amplifies sound waves whose frequency matches one of its own natural frequencies of vibration (its ''resonance frequencies''). The term "acoustic resonance" is sometimes used to nar ...

, as the shape of the human ear canal amplifies certain frequencies, especially those in the range of 2000 to 4000 Hz (the median pitches), at such a level that the sound triggers pain in our ears.

References

{{Reflist Sounds by type