Reference tone
Encyclopedia
A reference tone is a pure tone
corresponding to a known frequency, and produced at a stable sound pressure level (volume), usually by specialized equipment.
is a at 0dB
. It is meant to be used by audio engineers in order to adjust the playback equipment so that the accompanying media
is at a comfortable volume for the audience. In video production
, this tone is usually accompanied by a test card
so the video signal may be calibrated as well. It is sometimes played in sequence between a 100 Hz and 10 kHz tone to ensure an accurate response from the equipement at varying audio frequencies. This is also the "bleep" tone
commonly used to censor
obscene or sensitive audio content.
s used by musicians emit a tone of 440Hz, corresponding to a pitch
of A above Middle C
(A4). More sophisticated tuners offer a choice of other reference pitches to account for differences in tuning
. Some specialized tuners offer pitches used commonly on a particular instrument (standard guitar tuning, fifth intervals for string instruments, the open tones for various brass instruments).
Pure tone
A pure tone is a tone with a sinusoidal waveshape.A sine wave is characterized by its frequency, the number of cycles per second—or its wavelength, the distance the waveform travels through its medium within a period—and the amplitude, the size of each cycle...
corresponding to a known frequency, and produced at a stable sound pressure level (volume), usually by specialized equipment.
In media
The most common reference tone in audio engineeringAudio engineering
An audio engineer, also called audio technician, audio technologist or sound technician, is a specialist in a skilled trade that deals with the use of machinery and equipment for the recording, mixing and reproduction of sounds. The field draws on many artistic and vocational areas, including...
is a at 0dB
Decibel
The decibel is a logarithmic unit that indicates the ratio of a physical quantity relative to a specified or implied reference level. A ratio in decibels is ten times the logarithm to base 10 of the ratio of two power quantities...
. It is meant to be used by audio engineers in order to adjust the playback equipment so that the accompanying media
Electronic media
Electronic media are media that use electronics or electromechanical energy for the end-user to access the content. This is in contrast to static media , which today are most often created electronically, but don't require electronics to be accessed by the end-user in the printed form...
is at a comfortable volume for the audience. In video production
Video production
Video production is videography, the process of capturing moving images on electronic media even streaming media. The term includes methods of production and post-production...
, this tone is usually accompanied by a test card
Test card
A test card, also known as a test pattern in North America and Australia, is a television test signal, typically broadcast at times when the transmitter is active but no program is being broadcast...
so the video signal may be calibrated as well. It is sometimes played in sequence between a 100 Hz and 10 kHz tone to ensure an accurate response from the equipement at varying audio frequencies. This is also the "bleep" tone
Bleep censor
A bleep censor is the replacement of profanity or classified information with a beep sound , in television or radio...
commonly used to censor
Censorship
thumb|[[Book burning]] following the [[1973 Chilean coup d'état|1973 coup]] that installed the [[Military government of Chile |Pinochet regime]] in Chile...
obscene or sensitive audio content.
In music
Many electronic tunerElectronic tuner
The term electronic tuner can refer to a number of different things, depending which discipline you wish to study.In the Discipline of radio frequency electronics an electronic tuner is a device which tunes across a part of the radio frequency spectrum by the application of a voltage or appropriate...
s used by musicians emit a tone of 440Hz, corresponding to a pitch
Pitch (music)
Pitch is an auditory perceptual property that allows the ordering of sounds on a frequency-related scale.Pitches are compared as "higher" and "lower" in the sense associated with musical melodies,...
of A above Middle C
Middle C
C or Do is the first note of the fixed-Do solfège scale. Its enharmonic is B.-Middle C:Middle C is designated C4 in scientific pitch notation because of the note's position as the fourth C key on a standard 88-key piano keyboard...
(A4). More sophisticated tuners offer a choice of other reference pitches to account for differences in tuning
Musical tuning
In music, there are two common meanings for tuning:* Tuning practice, the act of tuning an instrument or voice.* Tuning systems, the various systems of pitches used to tune an instrument, and their theoretical bases.-Tuning practice:...
. Some specialized tuners offer pitches used commonly on a particular instrument (standard guitar tuning, fifth intervals for string instruments, the open tones for various brass instruments).
External links
- http://www.freesound.org/packsViewSingle.php?id=2103Downloadable reference tones, from The Freesound ProjectThe Freesound ProjectThe Freesound Project is a repository of Creative Commons licensed audio samples. Sounds uploaded to the website by its users cover a wide range of subjects, from field recordings to synthesized sound effects. All audio content in the repository is released under the Creative Commons Sampling Plus...
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