Loudness, it may also be referred to as volume, sound intensity is a quantity corresponding to the perceived loudness of sound. Sound intensity is an objective physical quantity, loudness is subjective psychological quantity. Xiao Bian think not only with the loudness of sound intensity is related also with frequency, different frequency, loudness level is not the same. Loudness constrained by the sound intensity, sound intensity level increased loudness level generally have improved.
Here is a simple example, to our childhood when watching TV will find an interesting thing, some television stations sound very small, need to turn the volume to maximum, changed the TV station after the sound is so big, that's because some television sound too large or too small caused.
Statistical standard loudness is calculated from the most basic audio digital sine wave (sine wave frequency component is the single most one signal, because this signal waveform is sinusoidal mathematical named any complicated signal - e.g. music signal, can be viewed as composed of many different frequencies, sizes compounded sine wave.)
To estimate the loudness of a pure tone in number, this can be a pure tone of 1000Hz pure tone sound intensity level is compared on the loudness. When these two voices that on hearing the same loudness, you can put the sound intensity level for the provision 1000Hz pure tone frequency pure tone loudness levels. Loudness level unit square (Phon), for example, a frequency of 1000Hz pure tones, if desired loudness reach 40 side, according to the equal-loudness curve, the sound pressure level which must be reached 40dB SPL.
These are odd billion pieces of music for everyone to share knowledge about the loudness, if you do not understand, are also welcome in the comments area!
