From Wikipedia, the free encyclopedia

An audio frequency (abbreviation: AF), or audible frequency is characterized as a periodic vibration whose frequency is audible to the average human. While the range of frequencies that any individual can hear is largely related to environmental factors, the generally accepted standard range of audible frequencies is 20 to 20,000 hertz. Frequencies below 20 Hz can usually be felt rather than heard, assuming the amplitude of the vibration is high enough. Frequencies above 20,000 Hz can sometimes be sensed by young people, but high frequencies are the first to be affected by hearing loss due to age and/or prolonged exposure to very loud noises.

Frequencies and descriptions

MIDI Note	Frequency (Hz)	Description	Sound File
C-2	4.09	Lowest note for Gregg Bailey's 64' PVC subcontrabass clarinet	N/A (inaudible)
C-1	8.18	Lowest organ note	N/A (inaudible)
C0	16.35	Lowest note for tuba, large pipe organs, Bösendorfer Imperial Grand Piano
C1	32.70	Lowest C on a standard 88-key piano.
C2	65.41	Lowest note for cello
C3	130.81	Lowest note for viola, mandola
C4	261.63	Middle C
C5	523.25	Lowest note for a piccolo.
C6	1046.50	Approximately the highest note reproducible by the average female human voice.
C7	2093	Highest note for a flute.
C8	4186	Highest note on a standard 88-key piano.
C9	8372
C10	16744	Approximately the tone that a typical CRT television emits while running.

Viewing the Audio Frequency Spectrum

Acoustic spectrogram of a young girl saying "Oh No". In this spectrogram, the vertical axis represents frequency linearly extending from 0 to 5.5 kHz, and the horizontal axis represents time over an interval of 700 milliseconds. Generated with Fatpigdog's PC based Real Time FFT Spectrum Analyzer.

The acoustic spectrum analyzer is a tool which converts a sound wave into a acoustic spectrogram. Historically, a spectrum analyzer has been an expensive piece of laboratory equipment. However, thanks to modern day advancements in the capabilities of personal computers, software based audio spectrum analyzers are available at low cost, providing easy access not only to industry professionals, but also to academicians, students and the lay hobbyist.

The acoustic spectrogram generated by the spectrum analyzer provides a time varying acoustic signature of the audio frequencies present in the source. For example, the acoustic signature of frequencies present in human speech can be characterized and used to identify the originator. This is of particular interest in the fields of law enforcement and forensic analysis. Similarly, analysis of the acoustic signature of a musical instrument may be used to characterize the sometimes subtle differences between a fine instrument and one that might be considered more mediocre.

See also

• Loudspeaker
• Piano Key Frequencies

External links

• Contrabass Mania
• Keyboard frequencies = naming of notes - The English and American system versus the German system