In the Spectogram view, simply clicking anywhere with the selection tool gives a vertical line to the top ruler, and shows at the bottom the exact sample, H:MM:SS, or other time coordinate you'd want.

I'm looking for the exact same functionality for frequency (Hz, or say musical pitch such as C7+14 cents) and intensity (-25dB).

Should Audacity not be able to do this, is there another tool that can read a WAV and do it? I've looked at Spec and it can't but it should be easy enough to modify (I'm a software engineer).

  • $\begingroup$ FYI There's a special name for a movable vertical line (or a movable horizontal line) that you can use to line up a point on a 2D plot with a scale or, to line up a point on one scale with another scale. It's called a cursor. A cursor can be an on-screen element in a graphical display, or it can be a mechanical thing, as in the case of an old-fashioned slide rule. $\endgroup$ Jan 2, 2019 at 18:00
  • $\begingroup$ Note that musical pitch may be quite different from the graphed/plotted frequency in a spectrograph. Frequency and intensity are also ambiguous, not exact, except in artificial data. So you need to better define your error bounds or estimation probabilities. $\endgroup$
    – hotpaw2
    Jan 2, 2019 at 22:01
  • $\begingroup$ Interesting, I've been doing GUIs since 1990 and wrote part of X11R5 and dozens of custom widgets. Never heard such a guideline called cursor, but I see that's indeed the exact term from sliderules. While you're obviously right, I don't think using a technical term even relative experts in the GUI field don't know would be an improvement. $\endgroup$ Jan 3, 2019 at 3:13
  • $\begingroup$ "Frequency and intensity are also ambiguous, not exact, except in artificial data." Sure, but there's a specific exact intensity graphed, at a specific point in the graph. While that number is quite iffy for various reasons, I want to know the number. My particular usage controls for time and frequency anyway; my primary interest is intensity and in addition having a frequency readout would double-check that I'm counting harmonics correctly. $\endgroup$ Jan 3, 2019 at 3:15

1 Answer 1


What you are asking is possible using heuristics but impossible in general because of the uncertainty principle. A single sample is just a value, it does not even make sense to ask about its frequency or frequencies. Roughly speaking (though not strictly true), the concept of "frequency" necessarily implies some form of repetition, thus it only applies to a range of samples, not a single sample. You can, of course, look at a fixed-length window around the sample you are interested in, but the result (both the number of frequencies and their accuracy) will depend a lot on the window length.

I think Sonic Visualiser has pretty decent heuristics for instantaneous frequencies.

  • $\begingroup$ I'm not asking for any more certainty than we have on the graph. Sure, maybe every bucket is an 8Hz range over 20ms, but there's definitely an intensity there used to color the graph, and I want to know what it is. (In the file I'm looking at there are single sustained notes and I know exactly what the frequency is anyway; I mainly need the intensity, and want the frequency mainly to double-check that I've guessed the right harmonic number and so on.) $\endgroup$ Jan 3, 2019 at 3:09
  • $\begingroup$ Could you clarify your question, then? The answer to "Should Audacity not be able to do this?" regarding your comment is obviously "yes, it should be able to." There is also the spectrum analyzer tool within Audacity, as well as the software I mentioned in my answer. $\endgroup$ Jan 3, 2019 at 8:54

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