#8 Dual spectrogram layer display

[Craig Stuart Sapp]

It would be nice to see the raw DFT spectrogram
"All Bins" and the phase-aligned peak analysis
"Frequencies" in the same Spectrogram display.

Attached is an illustration of what it would look
like. The functionality could probably be done
in one of two ways:

(1) add a fourth display type:
(a) All Bins
(b) Peak Bins
(c) Freqencies
(d) Combined --> shows (c) on top of (a)

(2) Add a check-box to overlay the "Frequencies" data
on the raw DFT display. Perhaps call the check box
"overlay", or "frequency overlay".

When viewing both sub-layers at the same time, it
would be preferrable if the raw DFT were displayed
in black and white, since it would be too confusing
if both sublayers were displayed in colour.

[Craig Stuart Sapp]

[Chris Cannam]

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I'm really not sure about this one. I think it looks pretty
tough to read.

Probably easy enough to implement though, so I'll notch up
the priority a bit and see about investigating.

[Craig Stuart Sapp]

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I agree that it looks a big confusing in the example, but
it will probably depend on the texture of the audio.

I am thinking the primary purpose would be for switching
between the raw dft spectrogram and the phase-aligned
frequencies spectrogram. Having the intermediate double
display would be helpful in comparing the two. This would
be done using the control-up/down arrow to switch between
the displays while looking at the same spectrogram.

I am also thinking in terms of the display in the Praat
speech analysis editor where the pitch analysis is displayed
on top of the raw spectrogram as shown in the attached
example figure. In this case it is easier to look at since
there is only one line of analysis data. (Praat does not
align the vertical axes of the spectrogram and pitch
analysis, so the alignment in the example is faked to
get them aligned).

[Craig Stuart Sapp]

Example frequency/dft spectrogram overlay from Praat