maad.spl.wav2pressure

maad.spl.wav2pressure(wave, gain, Vadc=2, sensitivity=-35, dBref=94)[source]

Convert wave amplitude to instantaneous sound pressure (p [Pa]).

Warning

Important: Previous versions of this function incorrectly calculated the: pressure conversion by omitting the division by 2 for the Vadc parameter. This resulted in pressure values that were twice as large as they should. If you want to correct the pressure values obtained with the previous version, you can simply divide the results by 2. 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 pressure values.

Parameters:

wavendarray-like or scalar: wave should already be normalized between -1 to 1 (depending on the number of bits) take the output of the function sound.load of maad module ndarray-like or scalar containing the raw sound waveform
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)

Returns:

pndarray-like or scalar: ndarray-like or scalar containing the sound waveform in pressure (Pa)

Examples

>>> w, fs = maad.sound.load('../data/cold_forest_daylight.wav') 
>>> maad.spl.wav2pressure(wave=w, gain=42)
    array([ 0.00481491,  0.00574187,  0.00576913, ..., -0.00185099,
    -0.00097856, -0.00168741])

Same result with 2 functions

>>> v = maad.spl.wav2volt(wave=w)
>>> maad.spl.volt2pressure(volt=v, gain=42) 
    array([ 0.00481491,  0.00574187,  0.00576913, ..., -0.00185099,
    -0.00097856, -0.00168741])        