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Equal-loudness contours. The phon is a logarithmic unit of loudness level for tones and complex sounds. Loudness is measured in sones, a linear unit.Human sensitivity to sound is variable across different frequencies; therefore, although two different tones may present an identical sound pressure to a human ear, they may be psychoacoustically perceived as differing in loudness.
The unit of measurement for loudness levels is the phon and is arrived at by reference to equal-loudness contours. By definition, two sine waves of differing frequencies are said to have equal-loudness level measured in phons if they are perceived as equally loud by the average young person without significant hearing impairment.
A graph of the A-, B-, C- and D-weightings across the frequency range 10 Hz – 20 kHz Video illustrating A-weighting by analyzing a sine sweep (contains audio). A-weighting is a form of frequency weighting and the most commonly used of a family of curves defined in the International standard IEC 61672:2003 and various national standards relating to the measurement of sound pressure level. [1]
A weighted curves follow a 40 phon curve while C weighted follows a 100 phon curve. [4] The three curves differ not in their measurement of exposure levels, but in the frequencies measured. A weighted curves allow more frequencies equal to or less than 500 Hz through, which is most representative of the human ear. [4]
For sound, the unit is the phon (1 kHz equivalent level). In the fields of acoustics and audio engineering, it is common to use a standard curve referred to as A-weighting , one of a set that are said to be derived from equal-loudness contours .
The post Dollar Weighted vs. Time Weighted: Investments appeared first on SmartReads by SmartAsset. Of the many ways to measure an investment, time- and dollar-weighting are two of the most common ...
The time-weighted rate of return measures how your investments have performed in a vacuum. Basically, for the assets that you purchased, it determines how much have they gained or lost value.
A weighting curve is a graph of a set of factors, that are used to 'weight' measured values of a variable according to their importance in relation to some outcome. An important example is frequency weighting in sound level measurement where a specific set of weighting curves known as A-, B-, C-, and D-weighting as defined in IEC 61672 [1] are used.