An echolocation call detection system comprising: an ultrasonic microphone configured to produce an analog signal representative of echolocation pulses and background noise; a first digital to analog converter configured to provide a first output signal representing a first trigger threshold; a first comparator configured to receive the analog signal at a first input and to receive the first output signal from the first digital to analog converter at a second input, the first comparator being configured to compare the first output signal and the analog signal and to produce a zero-crossing signal representative of zero crossings of the analog signal relative to the first trigger threshold set by the first digital to analog converter; a second digital to analog converter configured to provide a second output signal representing a test trigger threshold; characterized in that the echolocation call detection system further comprises a second comparator configured to receive and compare the analog signal and the second output signal from the second digital to analog converter and to provide a test signal representative of zero crossings of the analog signal relative to the test trigger threshold set by the second digital to analog converter; and a microprocessor coupled to the second comparator, to the first digital to analog converter, and to the second digital to analog converter, the microprocessor being configured to receive the test signal from the second comparator and to control the second digital to analog converter to optimize the second output signal to a most sensitive trigger threshold above sampled background noise, the microprocessor being further configured to periodically control the first digital to analog converter to adjust the first output signal from the first digital to analog converter to match the second output signal from the second digital to analog converter. an ultrasonic microphone configured to produce an analog signal representative of echolocation pulses and background noise; a first digital to analog converter configured to provide a first output signal representing a first trigger threshold; a first comparator configured to receive the analog signal at a first input and to receive the first output signal from the first digital to analog converter at a second input, the first comparator being configured to compare the first output signal and the analog signal and to produce a zero-crossing signal representative of zero crossings of the analog signal relative to the first trigger threshold set by the first digital to analog converter; a second digital to analog converter configured to provide a second output signal representing a test trigger threshold; characterized in that the echolocation call detection system further comprises a second comparator configured to receive and compare the analog signal and the second output signal from the second digital to analog converter and to provide a test signal representative of zero crossings of the analog signal relative to the test trigger threshold set by the second digital to analog converter; and a microprocessor coupled to the second comparator, to the first digital to analog converter, and to the second digital to analog converter, the microprocessor being configured to receive the test signal from the second comparator and to control the second digital to analog converter to optimize the second output signal to a most sensitive trigger threshold above sampled background noise, the microprocessor being further configured to periodically control the first digital to analog converter to adjust the first output signal from the first digital to analog converter to match the second output signal from the second digital to analog converter.