The Fugue

I struggled with this on and off for a couple of months. Finally I stumbled on the magic needed to get it working.

Dan Ellis has some MATLAB code for log-frequency spectrograms, but in Octave the graph lacks the custom y tick marks. Here’s the original code:

    yt = get(gca,'YTick');
    for i = 1:length(yt)
        ytl{i} = sprintf('%.0f',logffrqs(yt(i)));
    end
    set(gca,'YTickLabel',ytl);

This code gets the existing tick marks and labels them with the log frequency (instead of the frequency bin).
The problem is that Octave doesn’t populate YTick unless it was manually set already.

Here’s the working code:

    % octave doesn't populate YTick with its tick marks, so we have to set
    % our own. Besides, this way we get nice octave intervals.
    set(gca,'YTick',1:12:M);
    yt = get(gca,'YTick');
    for i = 1:length(yt)
        ytl{i} = sprintf('%.0f',logffrqs(yt(i)));
    end
    set(gca,'YTickLabel',ytl);