maad.spl.power2dBSPL

maad.spl.power2dBSPL(P, gain, Vadc=2, sensitivity=-35, dBref=94, pRef=2e-05)[source]

Convert power (amplitude²) to sound pressure level (L [dB]).

Warning

Important: Previous versions of this function incorrectly calculated the: volt conversion by omitting the division by 2 for the Vadc parameter. In dB SPL, this would lead to a 6 dB increase in the calculated sound pressure level. If you want to correct the SPL values obtained with the previous version, you can simply subtract 6 dB from the old results. This has been corrected in the version 1.5.1. Ensure you are using the latest version (>=1.5.1) to obtain accurate dB SPL values.

Parameters:

Pndarray-like or scalar: ndarray-like or scalar containing the power signal (P), for instance Sxx_power, the power spectral density (PSD)
gaininteger: Total gain applied to the sound (preamplifer + amplifier)
Vadcscalar, optional, default is 2Vpp (=>+/-1V): Maximal voltage (peak to peak) converted by the analog to digital convertor ADC
sensitivityfloat, optional, default is -35 (dB/V): Sensitivity of the microphone
dBrefinteger, optional, default is 94 (dBSPL): Pressure sound level used for the calibration of the microphone (usually 94dB, sometimes 114dB)
pRefSound pressure reference in the medium (air:20e-6 Pa, water:1e-6 Pa)

Returns:

Lndarray-like or scalar: ndarray-like or scalar containing the sound pressure level (L [dB])

See also

amplitude2dBSPL

Examples

>>> import numpy as np
>>> w, fs = maad.sound.load('../data/cold_forest_daylight.wav') 
>>> Sxx_power,tn,fn,_ = maad.sound.spectrogram (w, fs, nperseg=1024, mode='psd')  
>>> S_power_mean = np.mean(Sxx_power, axis=1)

Get instantaneous sound pressure level (L).

>>> maad.spl.power2dBSPL(S_power_mean, gain=42)    
    array([ 3.55439604e+01,  3.94219755e+01,  3.71509454e+01,  3.54860553e+01,
            3.20633292e+01,  2.85071055e+01,  2.65508217e+01,  2.56607733e+01,
            2.43080132e+01,  2.24405108e+01,  2.18647044e+01,  2.14653511e+01,
            ...
            -1.11242771e+01, -1.12703297e+01, -1.14085678e+01, -1.14487227e+01,
            -1.14906343e+01, -1.14980091e+01, -1.16907591e+01, -1.17027481e+01])