Pattern playback

Key takeaways

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

Reference excerpt

The pattern playback is an early talking device that was built by Dr. Franklin S. Cooper and his colleagues, including John M. Borst and Caryl Haskins, at Haskins Laboratories in the late 1940s and completed in 1950. There were several different versions of this hardware device. Only one currently survives. The machine converts pictures of the acoustic patterns of speech in the form of a spectrogram back into sound. Using this device, Alvin Liberman, Frank Cooper, and Pierre Delattre (later joined by Katherine Safford Harris, Leigh Lisker, and others) were able to discover acoustic cues for the perception of phonetic segments (consonants and vowels). This research was fundamental to the development of modern techniques of speech synthesis, reading machines for the blind, the study of speech perception and speech recognition, and the development of the motor theory of speech perception. To create sound, the pattern playback machine uses an arc light source which is directed against a rotating disk with 50 concentric tracks whose transparencies vary systematically in order to produce 50 harmonics of a fundamental frequency. The light is further projected against a spectrogram, whose reflectance corresponds to the sound pressure level of the partial of the signal, and is then directed towards a photovoltaic cell by which the light variation is converted into sound pressure variations. The pattern playback was last used in an experimental study by Robert Remez in 1976. The pattern playback now resides in the Museum at Haskins Laboratories in New Haven, Connecticut. The technique of pattern playback also now refers, more generally, to algorithms or techniques for converting spectrograms, cochleagrams, and correlograms from pictures back into sounds. A demonstration is in the TV show Adventure. Pioneering technology in psycholinguistics (CBS Television. 1953).

Digital pattern playback In the 1970s, digital pattern playbacks began to supplant the earlier version. An early prototype was developed by Patrick Nye, Philip Rubin, and colleagues at Haskins Laboratories. It combined a "Ubiquitous Spectrum Analyzer"[1] for automatic spectral analysis, along with a VAX GT-40 display processor for graphic manipulation of the displayed spectrogram, a form of "synthesis by art", and subsequent re-synthesis using a 40 channel filter bank. This hybrid hardware/software digital pattern playback was eventually replaced at Haskins Laboratories by the HADES analysis and display system, designed by Philip Rubin, and implemented in Fortran on the VAX family of computers. A more modern version has been described by Arai and colleagues [2]. An on-line demonstration is available [3].

See also Caryl Haskins Haskins Laboratories Alvin Liberman Reading machine Robert Remez Philip Rubin Spectrogram Motor theory of speech perception Speech synthesis Graphical sound

References

Bibliography Cooper, F.S., Liberman, A. M., & Borst, J. M., The interconversion of audible and visible patterns as a basis for research in the perception of speech. Proceedings of the National Academy of Sciences, 1951, 37, 318-325. Cooper, Franklin S., Delattre, Pierre C., Liberman, A. M., Borst, J. M. & Gerstman, L. J., Some experiments on the perception of synthetic speech sounds. The Journal of the Acoustical Society of America, 1952, 24, 597-606. Cooper, Franklin S., Some instrumental aids to research on speech. In Report of the fourth annual round table meeting on linguistics and language teaching. Washington, D.C.: Institute of Languages and Linguistics, Georgetown University, 1953, 46-53. J. M. Borst, The use of spectrograms for speech analysis and synthesis, J. Audio Eng. Soc., 4, 14-23, 1956. Liberman, Alvin M., Some results of research on speech perception. The Journal of the Acoustical Society of America, 1957, 29, 117-123. Remez, Robert E., Adaptation of the category boundary between speech and nonspeech: A case against feature detectors. Cognitive Psychology, 1979, 11, 38-57. Malcolm Slaney. Pattern Playback from 1950 to 1995. Proceedings of the 1995 IEEE Systems, Man and Cybernetics Conference. October 22–25, 1995, Vancouver, Canada. Malcolm Slaney, Pattern Playback in the 90's, in Advances in Neural Information Processing Systems 7, Gerald Tesauro, David Touretzky, and Todd Leen (eds.), MIT Press, Cambridge, MA, 1995. T. Arai, K. Yasu and T. Goto, Digital pattern playback, Proc. Autumn Meet. Acoust. Soc. Jpn., 429-430, 2005. T. Arai, K. Yasu and T. Goto, Digital pattern playback: Converting spectrograms to sound for educational purposes, Acoust. Sci. & Tech., 27(6), 393-395, 2006

Worked examples

Example 1 — a first encounter with Pattern playback

Start with the simplest possible case. Write down what Pattern playback 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 Pattern playback 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 Pattern playback 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 Pattern playback

In research: Pattern playback 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 Pattern playback 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: Pattern playback is common in secondary-school and first-year university syllabi. It links to neighbouring topics American inventions, Phonetics, Speech recognition, so understanding it makes those chapters shorter.
In everyday life: Look for Pattern playback 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.

How to study Pattern playback in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Pattern playback 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 Pattern playback out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Pattern playback in simple terms?

The pattern playback is an early talking device that was built by Dr. Franklin S.

Why does Pattern playback 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 Pattern playback?

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 Pattern playback.