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German psychologist William Stern invented the tone variator in 1897 to study human sensitivity to changes in pitch, going beyond the traditional psychophysical research of studying the sensitivity to differences in discrete tones. The instrument consists of an adjustable brass
Tone variator
. ''Brass Instrument Psychology''. University of Toronto. URL accessed 2006-07-01. *Kohl, Max.
Physical Apparatus
/ Vol. II. Apparatus and Supplies for General Use. Introduction to Physics. Mechanics. Wave Theory. Acoustics. Optics. Heat. Meteorology. Cosmology.'' Chemnitz, Germany. p 446. ;Publications * W. Stern, Autobiographical Essay in A History of Psychology in Autobiography, Murchinson, Carl (ed.) Vol. 1. Worcester, Mass: Clark University Press. * Rand Evans, "''The Just Noticeable Difference: Psychophysical instrumentation and the determination of sensory thresholds''". Proceedings of the Eleventh International Scientific Instrument Symposium, Bologna University, Italy, 9–14 September 1991. * Titchener, "''Experimental Psychology, a Manual of Experimental Practice: Volume II''", ''Quantitative Experiments, Part II''. Instructor's Manual. New York: MacMillan. p. 139. * G. M. Whipple, "''An analytic study of the memory image and the process of judgment in the discrimination of clangs and tones''". American Journal of Psychology, vol. 12, pp. 409–457; vol. 13, pp. 219–268. * Guy Montrose Whipple, "
'". American Journal of Psychology, Volume 14, pages 289–309, 1903 * RF Wyatt, "''A New Instrument for Measuring Pitch Discrimination''". The American Journal of Psychology, Volume 48, Issue 2, 1936. Pg 335. * {{cite journal , last1=Love , first1=Beryl F. , last2=Dawson , first2=Margaret K. , title=The Variation in Sound Intensity of Resonators and Organ Pipes with Blowing Pressure , journal=Physical Review , publisher=American Physical Society (APS) , volume=14 , issue=1 , date=1 June 1919 , issn=0031-899X , doi=10.1103/physrev.14.49 , pages=49–53, bibcode=1919PhRv...14...49L ;Websites * "Virtual Laboratory of Psychology: Instruments
. fh-potsdam.de (ed. the viewer gives a rotating view of the image) *
. phys.cwru.edu. *
Stern’s Tone variator, 1897
. scienceandsociety.co.uk. Hearing Perception Psychology experiments
German psychologist William Stern invented the tone variator in 1897 to study human sensitivity to changes in pitch, going beyond the traditional psychophysical research of studying the sensitivity to differences in discrete tones. The instrument consists of an adjustable brass resonator
A resonator is a device or system that exhibits resonance or resonant behavior. That is, it naturally oscillates with greater amplitude at some frequencies, called resonant frequencies, than at other frequencies. The oscillations in a resonator ...
, which is supplied with a constant flow of air across the opening at the top. Turning a graduated cam
Calmodulin (CaM) (an abbreviation for calcium-modulated protein) is a multifunctional intermediate calcium-binding messenger protein expressed in all eukaryotic cells. It is an intracellular target of the secondary messenger Ca2+, and the bind ...
on the front of the apparatus raises or lowers a piston
A piston is a component of reciprocating engines, reciprocating pumps, gas compressors, hydraulic cylinders and pneumatic cylinders, among other similar mechanisms. It is the moving component that is contained by a cylinder and is made gas-tig ...
in the bottom of the resonator, changing the volume of its interior, thus altering the sounded pitch over a continuous range.
The spiral-shaped cam is such that equal angles of rotation approximately correspond to equal changes in frequency. A dial on the front of the cam indicates the current resonance frequency and musical tone of the instrument.
Subsequent improvements to the device include the addition by G. M. Whipple of a gasometer
A gas holder or gasholder, also known as a gasometer, is a large container in which natural gas or town gas is stored near atmospheric pressure at ambient temperatures. The volume of the container follows the quantity of stored gas, with pressu ...
, in order to regulate the incoming air supply. A version of the device was also produced in which the bottom of the resonator was not displaced by a spiral, but by rack and pinion
A rack and pinion is a type of linear actuator that comprises a circular gear (the '' pinion'') engaging a linear gear (the ''rack''). Together, they convert rotational motion into linear motion. Rotating the pinion causes the rack to be driven ...
(see figure); in these, an eccentrically-operated pointer is used to indicate the frequency on the scale.
The instrument has been used in demonstrations, for tuning other instruments, and for research in psychology and otology
Otology is a branch of medicine which studies normal and pathological anatomy and physiology of the ear (hearing and vestibular sensory systems and related structures and functions) as well as their diseases, diagnosis and treatment. Otologic ...
. According to Stern, his research in the "apperception of change" began a "decisive metamorphosis" in his understanding:
See also
*Variator
A variator is a device that can change its parameters, or can change parameters of other devices.
Often a variator is a mechanical power transmission device that can change its gear ratio continuously (rather than in steps).
Examples
* Beier v ...
* Medicine
Medicine is the science and practice of caring for a patient, managing the diagnosis, prognosis, prevention, treatment, palliation of their injury or disease, and promoting their health. Medicine encompasses a variety of health care pract ...
and Health
Health, according to the World Health Organization, is "a state of complete physical, mental and social well-being and not merely the absence of disease and infirmity".World Health Organization. (2006)''Constitution of the World Health Organiza ...
* Audiology
Audiology (from Latin , "to hear"; and from Greek , ''-logia'') is a branch of science that studies hearing, balance, and related disorders. Audiologists treat those with hearing loss and proactively prevent related damage. By employing various ...
* Tuning Fork
A tuning fork is an acoustic resonator in the form of a two-pronged fork with the prongs (tines) formed from a U-shaped bar of elastic metal (usually steel). It resonates at a specific constant pitch when set vibrating by striking it against ...
* Cavity resonator
A resonator is a device or system that exhibits resonance or resonant behavior. That is, it naturally oscillates with greater amplitude at some frequencies, called resonant frequencies, than at other frequencies. The oscillations in a resonator ...
External articles and further reading
;General referencesTone variator
. ''Brass Instrument Psychology''. University of Toronto. URL accessed 2006-07-01. *Kohl, Max.
Physical Apparatus
/ Vol. II. Apparatus and Supplies for General Use. Introduction to Physics. Mechanics. Wave Theory. Acoustics. Optics. Heat. Meteorology. Cosmology.'' Chemnitz, Germany. p 446. ;Publications * W. Stern, Autobiographical Essay in A History of Psychology in Autobiography, Murchinson, Carl (ed.) Vol. 1. Worcester, Mass: Clark University Press. * Rand Evans, "''The Just Noticeable Difference: Psychophysical instrumentation and the determination of sensory thresholds''". Proceedings of the Eleventh International Scientific Instrument Symposium, Bologna University, Italy, 9–14 September 1991. * Titchener, "''Experimental Psychology, a Manual of Experimental Practice: Volume II''", ''Quantitative Experiments, Part II''. Instructor's Manual. New York: MacMillan. p. 139. * G. M. Whipple, "''An analytic study of the memory image and the process of judgment in the discrimination of clangs and tones''". American Journal of Psychology, vol. 12, pp. 409–457; vol. 13, pp. 219–268. * Guy Montrose Whipple, "
'". American Journal of Psychology, Volume 14, pages 289–309, 1903 * RF Wyatt, "''A New Instrument for Measuring Pitch Discrimination''". The American Journal of Psychology, Volume 48, Issue 2, 1936. Pg 335. * {{cite journal , last1=Love , first1=Beryl F. , last2=Dawson , first2=Margaret K. , title=The Variation in Sound Intensity of Resonators and Organ Pipes with Blowing Pressure , journal=Physical Review , publisher=American Physical Society (APS) , volume=14 , issue=1 , date=1 June 1919 , issn=0031-899X , doi=10.1103/physrev.14.49 , pages=49–53, bibcode=1919PhRv...14...49L ;Websites * "Virtual Laboratory of Psychology: Instruments
. fh-potsdam.de (ed. the viewer gives a rotating view of the image) *
. phys.cwru.edu. *
Stern’s Tone variator, 1897
. scienceandsociety.co.uk. Hearing Perception Psychology experiments