# Middle C spectrogram in RavenPro

I've been trying to perform a cross-correlation analysis between a Middle C sound (C4) and C5. I'm using the software RavenPro by Cornell to do the analysis. However, I've been unable to see a spectrogram for the middle C waveform.

As you can see, the waveform is visible, but I'm unable to discern a spectrogram here. Is there any reason this could happen?

In comparison to this, I'm seeing a spectrogram for C5, as you can see below

I've attached the youtube link for the both the sounds in the file, do let me know if anyone could provide any insight on this.

Middle C

C5

## 2 Answers

In addition to Matt L.'s point about zooming into the the bottom of the spectrogram for C4 to see 261Hz, your spectrogram plot is linear on the y-axis.

Check in Raven Pro if you can change the y-axis scale from linear to logarithmic, to better see your single frequency tones. I took a quick look at the Raven Pro manual and see in figure Figure 3.11 the Configure New Spectrogram Slice View dialog box, but it has no controls for frequency axis, the only logarithmic controls are over how the power (color) is computed. Overall, this is what the difference will be for 261Hz

The problem with middle C in the recording you use is that it's at least approximately a sinusoid with hardly any harmonics, so you can basically just see the fundamental frequency. In order to see it, you need to zoom in the low frequencies in your spectrogram.

The other note is not only one octave higher, but it's also played on the piano, so it has a nice overtone spectrum that is clearly visible in the spectrogram.