Fig. (8) Audacity is a particularly well-supported and well-documented open-source digital audio editor and recording application available for the Windows, macOS/OS X and Linux operating systems. It can be freely downloaded at https://www.audacityteam.org. Shown here are a series of breath sounds recorded at the neck in the author’s laboratory and displayed in the time-domain using Audacity. Although Audacity has an almost overwhelming array of features and options, three classes of features found in the “Effect” menu are likely to be of special interest to bio-acoustics investigators : the Amplify feature that scales the signal , the Normalize feature that “normalizes” the signal to a chosen maximum amplitude (e.g., 0 dB), and  three digital filtering options (Low Pass Filter, High-Pass Filter and Notch Filter). One final feature (Change Tempo) that may captivate some users is the ability to change the speed of a recording without changing the sound pitch, a feature of potential value in listening to heart sounds in tachycardic patients as well as to shorten the duration of verbal presentations.