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A sound with a loudness of 1 sone is judged equally loud as a 1 kHz tone with a sound pressure level of 40 decibels above 20 micropascals. [1] The phon is psychophysically matched to a reference frequency of 1 kHz. [2] In other words, the phon matches the sound pressure level in decibels of a similarly perceived 1 kHz pure tone. [3]
The threshold of hearing is plotted relative to a standardised curve that represents 'normal' hearing, in dB(HL) (hearing level). They are not the same as equal-loudness contours , which are a set of curves representing equal loudness at different levels, as well as at the threshold of hearing , in absolute terms measured in dB(SPL) (sound ...
The relationship between sound and noise levels is generally described in terms of a signal-to-noise ratio. With a background noise level between 35 and 100 dB, the threshold for 100% intelligibility is usually a signal-to-noise ratio of 12 dB. [3] 12 dB means that the signal should be roughly 4 times louder than the background noise. The ...
The decibel originates from methods used to quantify signal loss in telegraph and telephone circuits. Until the mid-1920s, the unit for loss was miles of standard cable (MSC). 1 MSC corresponded to the loss of power over one mile (approximately 1.6 km) of standard telephone cable at a frequency of 5000 radians per second (795.8 Hz), and matched closely the smallest attenuation detectable to a ...
Standards using different reference levels, give rise to differences in audiograms. The ASA-1951 standard, for example, used a level of 16.5 dB SPL (sound pressure level) at 1 kHz, whereas the later ANSI-1969/ISO-1963 standard uses 6.5 dB SPL , with a 10 dB correction applied for older people.
The speech banana is a banana-shaped region where the sounds of human languages appear on an audiogram. (An audiogram is a graphical representation of someone's ability to hear over a range of frequencies and loudness levels. Hearing on an audiogram is displayed as frequency in Hertz on the x-axis and loudness in decibels on the y-axis.)
The big three in sleep sounds are white noise, brown noise, and pink noise, but there are many other noise types, including purple noise, gray noise, and even black noise (a.k.a. good ol ...
Whether using a sound level meter or a noise dosimeter, the processing is somewhat similar. With a calibrated sound level meter, the incoming sounds are going to be picked up by the microphone and then measured by the internal electronic circuits. [5] The sound measurement that the device outputs can be filtered through an A, B, or C weighting ...