maad.spl.amplitude2dBSPL

maad.spl.amplitude2dBSPL(s, gain, Vadc=2, sensitivity=-35, dBref=94, pRef=2e-05)[source]

Convert signal (amplitude) to instantaneous sound pressure level (L [dB SPL]).

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:

sndarray-like or scalar: s is an amplitude signal (not energy signal : s² )
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 waveform in dB SPL (Sound Pressure level in dB)

See also

power2dBSPL

Examples

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

Get instantaneous sound pressure level (L).

>>> maad.spl.amplitude2dBSPL(S_amplitude_mean, gain=42)    
    array([ 33.54362056,  38.35057445,  35.93645686,  33.5848702 ,
            30.41177332,  27.22906075,  25.42079962,  24.42677998,
            22.89529647,  21.24902085,  20.75161999,  20.25268302,
            ...
            -12.18064124, -12.32827014, -12.48541472, -12.51967103,
            -12.54814367, -12.54536435, -12.75677825, -12.77745939])