def METHOD_NAME(unit=UNIT, ready_tone_spl=READY_TONE_SPL):
    # 3 approaches here (not exclusive):
    # a- get the mic sensitivity, the preamp gain and DAC parameters and do the math
    # b- treat the whole thing as a black box and do a calibration run (cf. people at Renard's lab)
    # c- use calibrated ready tone
    # The reference of acoustic pressure is 0dBSPL @ 1kHz which is threshold of hearing (20 μPa).
    # Usual calibration is 1 Pa (94 dBSPL) at 1 kHz
    # c) here we know that the ready tone is 55dB SPL at 5kHz, assuming a flat spectrum between
    # 1 and 5 kHz, and observing the peak value on the 5k at the microphone.
    if unit == 'dBFS':
        return 1.0
    distance_to_the_mic = .155
    peak_value_observed = 60
    rms_value_observed = np.sqrt(2) / 2 * peak_value_observed
    fac = 10 ** ((ready_tone_spl - 20 * np.log10(rms_value_observed)) / 20) * distance_to_the_mic
    return fac