Listening to ultrasound is a useful feature in special measurement equipment. High frequency can be converted by means of different technologies in order to determine bats in nature or for monitoring of processes in different industries. Of course, this requires a conversion or shift of the original high frequency sound to audible frequencies. Traditionally, heterodyne technologies – which can be completely realized by analogous electronics – are used in order to find leaks or fault in bearings. These result in an audible signals which represent only a narrow high-frequency band which is shifted to a lower one. The physically exiting frequencies outside this band are lost. The application of broadband sensors (for airborne and structural borne noise) enables an improved access to the physical and technical processes (friction, turbulence, cracks, discharges and more). This broadband ultrasound acoustics is "translated" to the audio range by means of a real-time vocoder procedure which preserves all effects of amplitude modulation and frequency distribution. Consequently, testers have a more direct interaction to the real monitoring processes. The procedures are exemplified for machine fault and material failure. The data are compressed by a factor depending on the application. The converted output signals exhibit a similar but scaled frequency characteristics. The loss of information can be neglected for the most industrial acoustic pattern. Almost all interesting parameters (1/n octave band levels, crest, kurtosis and more) can be estimated with a sufficient accuracy. That means that the audio-channel of the ultrasound equipment can be efficiently used for long-term recording of data. It could be demonstrated that the technology works for monitoring of fault trending. Examples are given for bearing faults and material failure. An important side effect is an audible insight in the sometimes fascinating world of ultrasound in technical processes.