Before revision: is that the ear is not an abstract spectrograph: it "calculates" the Fourier transform of the sound signal in a narrow time window, but the slower variations are seen as temporal evolution and not as pitch.
After revision: is that the ear is not an abstract spectrograph: it "calculates" the Fourier transform of the audio signal in a narrow time window, but the slower variations are seen as temporal evolution and not as pitch.