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For other uses, see Acoustics (disambiguation).
Artificial omni-directional sound source in an anechoic chamber
Acoustics is the interdisciplinary science that deals with the study of all mechanical waves in gases, liquids, and solids including vibration, sound, ultrasound and infrasound. A scientist who works in the field of acoustics is an acoustician while someone working in the field of acoustics technology may be called an acoustical engineer. The application of acoustics is present in almost all aspects of modern society with the most obvious being the audio and noise ...view middle of the document...
1 Wave propagation: pressure levels
* 2.2 Wave propagation: frequency
* 2.3 Transduction in acoustics
* 3 Acoustician
* 3.1 Education
* 4 Subdisciplines
* 4.1 Archaeoacoustics
* 4.2 Aeroacoustics
* 4.3 Acoustic signal processing
* 4.4 Architectural acoustics
* 4.5 Bioacoustics
* 4.6 Electroacoustics
* 4.7 Environmental noise and soundscapes
* 4.8 Musical acoustics
* 4.9 Psychoacoustics
* 4.10 Speech
* 4.11 Ultrasonics
* 4.12 Underwater acoustics
* 4.13 Vibration and dynamics
* 5 Professional societies
* 6 Academic journals
* 7 See also
* 8 References
* 9 Further reading
* 10 External links
History of acoustics
Early research in acoustics
The fundamental and the first 6 overtones of a vibrating string. The earliest records of the study of this phenomenon are attributed to the philosopher Pythagoras in the 6th century BC.
In about 20 BC, the Roman architect and engineer Vitruvius wrote a treatise on the acoustic properties of theatres including discussion of interference, echoes, and reverberation—the beginnings of architectural acoustics.
In the 6th century BC, the ancient Greek philosopher Pythagoras wanted to know why some musical intervals seemed more beautiful than others, and he found answers in terms of numerical ratios representing the harmonic overtone series on a string. He is reputed to have observed that when the lengths of vibrating strings are expressible as ratios of integers (e.g. 2 to 3, 3 to 4), the tones produced will be harmonious. If, for example, a string sounds the note C when plucked, a string twice as long will sound the same note an octave lower. The tones in between are then given by 16:9 for D, 8:5 for E, 3:2 for F, 4:3 for G, 6:5 for A, and 16:15 for B, in ascending order.
Aristotle (384-322 BC) understood that sound consisted of contractions and expansions of the air "falling upon and striking the air which is next to it...", a very good expression of the nature of wave motion.
Principles of acoustics were applied since ancient times : Roman theatre in the city of Amman.
The physical understanding of acoustical processes advanced rapidly during and after the Scientific Revolution. Mainly Galileo Galilei (1564–1642) but also Marin Mersenne (1588–1648), independently, discovered the complete laws of vibrating strings (completing what Pythagoras and Pythagoreans had started 2000 years earlier). Galileo wrote "Waves are produced by the vibrations of a sonorous body, which spread through the air, bringing to the tympanum of the ear a stimulus which the mind interprets as sound", a remarkable statement that points to the beginnings of physiological and psychological acoustics. Experimental measurements of the speed of sound in air were carried out successfully between 1630 and 1680 by a number of investigators, prominently Mersenne. Meanwhile Newton (1642–1727)...