Did you mean something like this? It turns out that Audacity does this, but I couldn't convince it to use the same vertical scaling for both plots, making it difficult to compose them together in GIMP. But there's an "export" button that generates a text file of values, and I've got GnuPlot, so ...
There were a bunch of options on the Audacity "analyze spectrum" dialogue that I'm really not sure I understand right, so I'm not sure what I got (pretty much the default) is the most useful version.)
(no subject)
It turns out that Audacity does this, but I couldn't convince it to use the same vertical scaling for both plots, making it difficult to compose them together in GIMP. But there's an "export" button that generates a text file of values, and I've got GnuPlot, so ...
There were a bunch of options on the Audacity "analyze spectrum" dialogue that I'm really not sure I understand right, so I'm not sure what I got (pretty much the default) is the most useful version.)