Beat (acoustics)

In acoustics, a beat is an interference pattern between two sounds of slightly different frequencies, perceived as a periodic variation in volume whose rate is the difference of the two frequencies.

When tuning instruments that can produce sustained tones, beats can readily be recognized. Tuning two tones to a unison will present a peculiar effect: when the two tones are close in pitch but not identical, the difference in frequency generates the beating. The volume varies like in a tremolo as the sounds alternately interfere constructively and destructively. As the two tones gradually approach unison, the beating slows down and may become so slow as to be imperceptible.

Mathematics and physics of beat tones

This phenomenon is best known in acoustics or music, though it can be found in any linear system. If a graph is drawn to show the function corresponding to the total sound of two strings, it can be seen that maxima and minima are no longer constant as when a pure note is played, but change over time: when the two waves are nearly 180 degrees out of phase the maxima of one wave cancel the minima of the other, whereas when they are nearly in phase their maxima sum up, raising the perceived volume.

Beat

Beat or beats may refer to:

Business and organisations

Common usage

Swatch Internet Time

Swatch Internet Time (or beat time) is a decimal time concept introduced in 1998 by the Swatch corporation as part of their marketing campaign for their line of "Beat" watches.

Instead of hours and minutes, the mean solar day is divided up into 1000 parts called ".beats". Each .beat is equal to one decimal minute in the French Revolutionary decimal time system and lasts 1 minute and 26.4 seconds (86.4 seconds) in standard time. Times are notated as a 3-digit number out of 1000 after midnight. So, @248 would indicate a time 248 .beats after midnight representing 248/1000 of a day, just over 5 hours and 57 minutes.

There are no time zones in Swatch Internet Time; instead, the new time scale of Biel Meantime (BMT) is used, based on Swatch's headquarters in Biel, Switzerland and equivalent to Central European Time, West Africa Time, and UTC+01. Unlike civil time in Switzerland and many other countries, Swatch Internet Time does not observe daylight saving time.

History

Swatch Internet Time was announced on October 23, 1998, in a ceremony at the Junior Summit '98, attended by Nicolas G. Hayek, President and CEO of the Swatch Group, G.N. Hayek, President of Swatch Ltd., and Nicholas Negroponte, founder and then-director of the MIT Media Lab. During the Summit, Swatch Internet Time became the official time system for Nation1, an online country (supposedly) created and run by children.

Beat (song)

"BEAT" is the fourth single from Japanese pop singer Kaela Kimura. It was released as the second single from her album, Circle, on October 5, 2005. It peaked at #7 on the Oricon charts.

Track listing

References

Acoustics (disambiguation)

Acoustics is the interdisciplinary science that deals with the study of all mechanical waves in gases, liquids, and solids.

Acoustics may also refer to:

See also