AirSoundAttenuation

AirSoundAttenuation[spec,frequency]

returns the sound attenuation coefficient in moist air for the specified parameters spec for frequency.

AirSoundAttenuation[spec,frequency, distance]

returns the sound attenuation factor for the specified parameters at distance.

AirSoundAttenuation[spec,frequency, distance,sl]

returns the sound level at distance given the source sound level sl.

AirSoundAttenuation[spec,audio, distance]

transforms audio based on the distance from the source.

Details and Options

  • spec should be an association with keys corresponding to the following parameters:
  • "DewPointTemperature"dew point temperature
    "DryBulbTemperature"dry bulb temperature
    "HumidityRatio"humidity ratio
    "Pressure"air pressure
    "RelativeHumidity"relative humidity
    "WetBulbTemperature"wet bulb temperature
  • "DryBulbTemperature" is necessary, as is the inclusion of one of the other temperature or humidity measures. "Pressure" is optional.
  • Unless specified, "Pressure" is assumed to have the value of Quantity[101325,"Pascals"].
  • In the case of inclusion of multiple humidity measures, values will be used in the following order of precedence: "DewPointTemperature", "RelativeHumidity", "HumidityRatio", "DewPointTemperature".
  • frequency should be a Quantity within the range of 50 Hz to 20 kHz.
  • distance should be a Quantity of dimension length.
  • The sound attenuation coefficient is returned in units of decibels per unit length.
  • The sound attenuation factor is the numerical factor by which the source sound level is scaled down.
  • The following options can be given:
  • MethodAutomaticmethod to use
    UnitSystem$UnitSystemspecify units in returned quantities
  • UnitSystem supports the settings "Imperial" and "Metric". The sound attenuation coefficient is returned in units of decibels per meter in metric units and units of decibels per foot in imperial units.
  • Method supports the method "IncludeDispersion" that adjusts to account for dispersion of sound due to distance traveled. The option "ReferenceDistance" allows the distance that the source sound level or audio was sampled at to be specified.
  • sl should be a decibel Quantity or a unit compatible with decibels such as nepers, octaves or decades.
  • Sound levels are returned in the same units as sl.
  • audio should be a valid Audio object. The result will be an Audio object where the sound is attenuated according to frequency and distance.

Examples

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Basic Examples  (3)

Compute the sound attenuation coefficient:

Determine the sound level of a 75 decibel 200 Hz source at 2000 feet due to sound attenuation:

Transform audio based on atmospheric conditions and distance:

Scope  (5)

Calculate the sound attenuation factor using distance and frequency:

Compute the attenuated sound level in octaves:

Visualize the attenuation coefficient as a function of frequency:

Examine how the sound attenuation coefficient changes with temperature:

Compare to the behavior of the sound attenuation coefficient with increasing relative humidity:

Explore how decibels diminish over distance:

Options  (4)

Method  (2)

Account for sound dispersion for a 75 decibel 200 Hz source at 2000 feet:

Apply dispersion to audio:

Compare against the sound levels without dispersion:

UnitSystem  (2)

By default, results are in "Metric" units:

Set UnitSystem to "Imperial" to specify that results be in decibels per foot:

UnitConvert can also be used to adjust the units:

Possible Issues  (3)

Dry bulb temperature should equal or exceed the wet bulb point temperatures:

Dry bulb temperature should equal or exceed the dew point temperatures:

A dry bulb temperature is needed for calculations:

Frequencies should be between 50 Hz and 20 kHz:

Wolfram Research (2020), AirSoundAttenuation, Wolfram Language function, https://reference.wolfram.com/language/ref/AirSoundAttenuation.html.

Text

Wolfram Research (2020), AirSoundAttenuation, Wolfram Language function, https://reference.wolfram.com/language/ref/AirSoundAttenuation.html.

BibTeX

@misc{reference.wolfram_2020_airsoundattenuation, author="Wolfram Research", title="{AirSoundAttenuation}", year="2020", howpublished="\url{https://reference.wolfram.com/language/ref/AirSoundAttenuation.html}", note=[Accessed: 16-January-2021 ]}

BibLaTeX

@online{reference.wolfram_2020_airsoundattenuation, organization={Wolfram Research}, title={AirSoundAttenuation}, year={2020}, url={https://reference.wolfram.com/language/ref/AirSoundAttenuation.html}, note=[Accessed: 16-January-2021 ]}

CMS

Wolfram Language. 2020. "AirSoundAttenuation." Wolfram Language & System Documentation Center. Wolfram Research. https://reference.wolfram.com/language/ref/AirSoundAttenuation.html.

APA

Wolfram Language. (2020). AirSoundAttenuation. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/AirSoundAttenuation.html