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MAINT: Remove the air attenuation function #157

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Merged
mberz merged 1 commit into from
Mar 18, 2026
Merged

MAINT: Remove the air attenuation function #157

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5 changes: 0 additions & 5 deletions pyrato/__init__.py
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Original file line number Diff line number Diff line change
Expand Up @@ -7,10 +7,6 @@
__version__ = '0.4.1'


from .parametric import (
air_attenuation_coefficient,
)

from . import edc
from . import parameters
from . import dsp
Expand All @@ -23,5 +19,4 @@
'dsp',
'analytic',
'parametric',
'air_attenuation_coefficient',
]
72 changes: 0 additions & 72 deletions pyrato/parametric.py
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Original file line number Diff line number Diff line change
Expand Up @@ -96,78 +96,6 @@ def energy_decay_curve(
return pf.TimeData(np.reshape(edc, (*matching_shape, times.size)), times)


def air_attenuation_coefficient(
frequency,
temperature=20,
humidity=50,
atmospheric_pressure=101325):
"""Calculate the attenuation coefficient m for the absorption caused
by friction with the surrounding air.

Parameters
----------
frequency : double
The frequency for which the attenuation coefficient is calculated.
When processing in fractional octave bands use the center frequency.
temperature : double
Temperature in degrees Celsius.
humidity : double
Humidity in percent.
atmospheric_pressure : double
Atmospheric pressure.

Returns
-------
attenuation_coefficient : double
The resulting attenuation coefficient.

"""
from pyfar.classes.warnings import PyfarDeprecationWarning
import warnings

warnings.warn(
'Will be replaced by respective function in pyfar before v1.0.0',
PyfarDeprecationWarning, stacklevel=2)

# room temperature in Kelvin
t_K = temperature + 273.16
p_ref_kPa = 101.325
p_kPa = atmospheric_pressure/1000.0

# determine molar concentration of water vapor
tmp = (
(10.79586 * (1.0 - (273.16/t_K))) -
(5.02808 * np.log10((t_K/273.16))) +
(1.50474 * 0.0001 * (1.0 - 10.0 ** (-8.29692*((t_K/273.16) - 1.0)))) +
(0.42873 * 0.001 * (-1.0 + 10.0 ** (-4.76955*(1.0 - (273.16/t_K))))) -
2.2195983)

# molar concentration water vapor in percent
molar_water_vapor = (humidity * 10.0 ** tmp) / (p_kPa/p_ref_kPa)

# determine relaxation frequencies of oxygen and nitrogen
relax_oxygen = ((p_kPa/p_ref_kPa) * (24.0 + (
4.04 * 10000.0 * molar_water_vapor * (
(0.02 + molar_water_vapor) / (0.391 + molar_water_vapor)))))

relax_nitrogen = ((p_kPa/p_ref_kPa) * (
(t_K / 293.16) ** (-0.5)) *
(9.0 + 280.0 * molar_water_vapor * np.exp(
-4.17 * (((t_K / 293.16) ** (-0.3333333)) - 1.0))))

# Neper/m -> dB/m
air_abs_coeff = ((frequency**2 * (
(1.84 * 10.0**(-11.0) * (p_ref_kPa / p_kPa) * (t_K/293.16)**0.5) +
((t_K/293.16)**(-2.5) * (
(1.278 * 0.01 * np.exp(-2239.1/t_K) / (
relax_oxygen + (frequency**2)/relax_oxygen)) +
(1.068 * 0.1 * np.exp((-3352.0/t_K) / (
relax_nitrogen + (frequency**2)/relax_nitrogen))))))
) * 20.0 / np.log(10.0) / (np.log10(np.exp(1.0)) * 10.0))

return air_abs_coeff


def critical_distance(
volume,
reverberation_time):
Expand Down