science

Tone variator

Tone variator is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Tone variator rather than just read about it. In short: 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, which is supplied with a constant flow of air across the opening at the top.

Key takeaways

Tone variator belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Tone variator to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Tone variator from memory before moving on to harder problems.

Reference excerpt

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, which is supplied with a constant flow of air across the opening at the top. Turning a graduated cam on the front of the apparatus raises or lowers a piston 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, 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 (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. According to Stern, his research in the "apperception of change" began a "decisive metamorphosis" in his understanding:

The issue [apperception of change] was raised by a psycho-physical proposition: I wanted to discover the 'sensitivity,' not as Fechner and his successors, for two barely distinguishable constant stimuli, but for the continuous change of one stimulus into another. At first I conceived the problem in purely sensationist terms, sought to determine thresholds experimentally, raised the question of the possible existence of 'transition feelings,' etc. Soon, however, the sphere of my inquiry widened in the direction of descriptive and humanistic problems.

See also Variator Medicine and Health Audiology Tuning fork Cavity resonator

External articles and further reading General references "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, "Studies in pitch discrimination". 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. ISSN 0002-9556 Love, Beryl F.; Dawson, Margaret K. (1 June 1919). "The Variation in Sound Intensity of Resonators and Organ Pipes with Blowing Pressure". Physical Review. 14 (1). American Physical Society (APS): 49–53. Bibcode:1919PhRv...14...49L. doi:10.1103/physrev.14.49. ISSN 0031-899X. Websites "Virtual Laboratory of Psychology: Instruments: Stern Variator". fh-potsdam.de (ed. the viewer gives a rotating view of the image) "Tone variator". phys.cwru.edu. "Stern’s Tone variator, 1897". scienceandsociety.co.uk.

Illustrations

Tone variator: Tone variator with rack and pinion design. — Tone variator with rack and pinion design.

Worked examples

Example 1 — a first encounter with Tone variator

Start with the simplest possible case. Write down what Tone variator claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Tone variator before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Tone variator ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Tone variator

In research: Tone variator appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Tone variator in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Tone variator is common in secondary-school and first-year university syllabi. It links to neighbouring topics Hearing, Perception, Psychology experiments, so understanding it makes those chapters shorter.
In everyday life: Look for Tone variator outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Tone variator in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Tone variator means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Tone variator out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Tone variator in simple terms?

Why does Tone variator matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Tone variator?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Tone variator.