An acoustic monitor, comprising: a digital signal processor; a memory; an emitter; a microphone including analog signal conditioning circuitry configured to receive an acoustic test signal at a test frequency and sound pressure level and being in signal communication with the digital signal processor, a low-pass filter configured for attenuating frequencies above the frequency range of interest, generally 20 Hz to 80 kHz; wherein the memory is configured to store a reference acoustic power of a reference acoustic signal for each frequency band, the reference acoustic power being obtained in a self-calibration mode, while in a sound-proof enclosure or anechoic chamber to minimize background noise; wherein the digital signal processor is configured to step the emitter through all the frequency bands, at full output, while measuring the acoustic power, one band at a time; and wherein the memory is configured to store the acoustic power for each band, to be used as reference values for self-testing during actual operation; and wherein the digital signal processor is configured to initiate a self-test in which the measured real-time power spectrum of the emitter is first compared with the stored reference values, to select the optimal filter band, that is, the frequency, to be used for the test, wherein the optimal filter band is the one for which the reference value, that is, the acoustic power of the emitter, exceeds the real-time power in the spectrum of background noise, by the greatest amount; and to activate the emitter using the optimal test frequency for a period of time, while the acoustic power for the corresponding filter band is measured; wherein to pass the self-test, the measured acoustic power must be equal to the emitter output, for the corresponding filter band, within a certain tolerance. a digital signal processor; a memory; an emitter; a microphone including analog signal conditioning circuitry configured to receive an acoustic test signal at a test frequency and sound pressure level and being in signal communication with the digital signal processor, a low-pass filter configured for attenuating frequencies above the frequency range of interest, generally 20 Hz to 80 kHz; wherein the memory is configured to store a reference acoustic power of a reference acoustic signal for each frequency band, the reference acoustic power being obtained in a self-calibration mode, while in a sound-proof enclosure or anechoic chamber to minimize background noise; wherein the digital signal processor is configured to step the emitter through all the frequency bands, at full output, while measuring the acoustic power, one band at a time; and wherein the memory is configured to store the acoustic power for each band, to be used as reference values for self-testing during actual operation; and wherein the digital signal processor is configured to initiate a self-test in which the measured real-time power spectrum of the emitter is first compared with the stored reference values, to select the optimal filter band, that is, the frequency, to be used for the test, wherein the optimal filter band is the one for which the reference value, that is, the acoustic power of the emitter, exceeds the real-time power in the spectrum of background noise, by the greatest amount; and to activate the emitter using the optimal test frequency for a period of time, while the acoustic power for the corresponding filter band is measured; wherein to pass the self-test, the measured acoustic power must be equal to the emitter output, for the corresponding filter band, within a certain tolerance.