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The risk of negative health effects from sound exposures (be it noise or music) is primarily determined by the intensity of the sound , duration of the event, and frequency of that exposure. [9] These three factors characterize the overall sound energy level that reaches a person's ears and can be used to calculate a noise dose.
being approximately the lowest sound intensity hearable by an undamaged human ear under room conditions. The proper notations for sound intensity level using this reference are L I /(1 pW/m 2) or L I (re 1 pW/m 2), but the notations dB SIL, dB(SIL), dBSIL, or dB SIL are very common, even if they are not accepted by the SI. [6]
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]
To keep the volume at a safe level, limit the volume to 60-70% of the maximum volume. A good rule of thumb is that you should still be able to hear a person talking at an arm’s length from you.
In other media, such as underwater, a reference level of 1 μPa is used. [9] These references are defined in ANSI S1.1-2013. [10] The main instrument for measuring sound levels in the environment is the sound level meter. Most sound level meters provide readings in A, C, and Z-weighted decibels and must meet international standards such as IEC ...
Music played at 85 decibels, or level of sounds, for prolonged periods of times can cause hearing damage, for instance, sound levels at some rock concerts can reach 110-120 A-weighted decibels, and at those levels, the maximum daily limit set by most standards and regulations can be reached in less than one minute of exposure. [8] [9]
Signal-to-noise ratio (SNR), however, is the ratio between the noise floor and an arbitrary reference level or alignment level. In "professional" recording equipment, this reference level is usually +4 dBu (IEC 60268-17), though sometimes 0 dBu (UK and Europe – EBU standard Alignment level).
The levels are weighted with frequency relative to a standard graph known as the minimum audibility curve, which is intended to represent "normal" hearing. The threshold of hearing is set at around 0 phon on the equal-loudness contours (i.e. 20 micropascals , approximately the quietest sound a young healthy human can detect), [ 15 ] but is ...