Reference tone
It has been suggested that this article be merged with Musical tone, Pure tone, Signal tone and Standard test tone. (Discuss) Proposed since August 2014. |
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.
In media
The most common reference tone in audio engineering is a ⓘ at −20dB. 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 programming 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 equipment at varying audio frequencies. This is also the "bleep" tone commonly used to censor obscene or sensitive audio content.
In music
Many electronic tuners 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).
See also
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