I recently used an audible recording of a time domain waveform acquired with the VibXpert to help demonstrate the value of the actual “audible” sound of a bearing fault during a recent condition monitoring survey (baseline measurements) of a multistage circulation pump. As we know, the time domain waveform signal is truly the “raw” data of vibration measurements. In this particular case, the frequency domain (FFT plot) measurements showed very low vibration amplitude levels and the determining factor for the early detection of the bearing fault was primarily the use of time domain waveform signals. Frequency domain (spectra plots) along with time domain (waveform plots) was presented to the customer for their review.  Also, an “audible” recording of the time domain waveform signal was presented to the customer for review with very favorable results. The customer conveyed that the “actual” bearing impacting sound represented by the time waveform recording was easier to comprehend then reviewing the time signal plot. The customer stated that he felt like he was getting a combination of “ultra sound” technology along with vibration analysis and was very satisfied with the results.The VibXpert® data collectors allow you to listen to the raw data collected on equipment.  The OMNITREND® software allows time domain waveform data to be played back in the comfort of your office.  In certain situations these capabilities can be a great analysis tool. I have successfully used these capabilities in the past to capture “random” impacting events of ultra-slow operating equipment such as gear reducers on conveyor drives and building structure movement in connection with sensitive types of hospital equipment. Bottom line, I am planning on utilizing these capabilities much more in the future for illustrating time domain waveform signals to my customers. —Ray Wonderly with ADVANCED MAINTENANCE TECHNOLOGIES – http://www.amt-vibration.com/