Spectrogram View Question

A recent posting had a tone stuck in a voice performance.

I created a notch filter at 830Hz based on a completely lucky guess. I blew up my screen as tall as it would go. It worked. How was I supposed to make the display tell me where that line was in frequency?

Koz

That’ll get you in the right ball park.

For a more accurate indication, a better tool is Plot Spectrum. Select a part that is mostly silent apart from the unwanted “tone”, and you should see a spike at that frequency. Increase the “Size” parameter to increase frequency resolution, and use the mouse to select the peak.

Writing that down…

Koz

816Hz.

I guessed the laptop fan. We’ll see.

Koz

There’s an Audacity app for that: view / toolbars / spectral selection toolbar

spectral selection

Which versions of Audacity can do that?

Koz

I don’t know when it was introduced, but it’s in version 2.3.2 …

IIRC it’s off by default in version 3. It’s activated via the toolbars menu: spectral selection

I’ll try it when it calms down a bit.

Koz

3.6.1 or 3.6.2 depending on the machine. Yes I know I’m going to run into trouble with people on 3.7.x

Koz

The Plot Spectrum tool in the Analyze menu will also help you find the frequency to apply the Notch filter to. When in the Plot Spectrum window, move the mouse cursor over the peak and it will tell you the exact frequency.

Yes. If you can see it. In this case, the 816Hz tone was pure enough to vanish if the Plot Spectrum Size setting is too high. The display is smaller than the pixel count of my screen. In this case, I did it backwards. I kept increasing the graphic size of the Spectrogram Window until I could get into the ballpark. Then open Plot Spectrum and decrease the Size (accuracy) until the tone appeared.

Again in this instance, the original guess of 830Hz caused the bad sound to decrease substantially and the following gentle Noise Reduction of the Beast resulted in an acceptable presentation.

Koz

For removing that unwanted tone, the Spectral Delete effect would probably be the best tool.

Which I know about now.

Koz

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