A heart-sound monitor and esophageal stethoscope which makes use of fluidic aminar proportional amplifiers (LPAs). These LPA's are used to sense and amplify incoming acoustic pressure signals, such as heart signals. Moreover, the fluidic monitor is able to monitor a fetus heartbeat while eliminating the acoustic interference present from the mother's heartbeat. In this case, the LPA acts not only as an amplifier, but as an acoustic filter as well.