1. Apparatus for improving aural and visual discrimination and detection of heart sounds comprising: a transducer means for converting said heart sounds to electrical signals, amplifying means connected to said transducer means for amplifying said electrical signals to provide an amplifier output, adjustable high pass filter means for receiving and filtering said amplifier output to produce a filtered output having frequency components, wherein said high pass filter means has a cutoff frequency, below which said amplifier output is attenuated and above which said amplifier output is passed, oscillator means for providing an audio frequency carrier having frequency components, modulator means connected to said adjustable filter means and to said oscillator means for modulating said audio frequency carrier with said filtered output so as to generate a modulator output representing a sum and a difference of said frequency components of said filtered output and said audio frequency carrier, high pass filter means connected to said modulator means for filtering said modulator output to produce a further filtered signal representing the sum of said frequency components of said filtered output and said audio frequency carrier, and sound intensity discriminating means connected to said adjustable high pass filter means for producing a visual display of said filtered output, whereby to provide visual detection and discrimination of inaudible heart sound events.