WaveSurfer is an good free-download product. I especially like the spectrogram. There used to be a pitch detector, but I can't find it now. The right-click feature which is supposedly invoked by control-click on the Mac is not working for me. But my main reason for putting in this review is to complain that the "update" that I just downloaded seems to be the same as the one I downloaded on Nov 23, 2016, and even so I can't install it on my Mac (10.9.2). They are both version wavesurfer-1.8.8p5-osx-i386, although the dmg sizes are slightly different. Even so, I attempted to install the latest one by double-clicking on the dmg file, but I got a warning message that says "The following disk images couldn't be opened -- Image: wavesurfer-1.8.8p5-... Reason: no mountable file systems" . I hit the OK button, but nothing happens.