Science Buddies: "Ask an Expert"

I'm using Audacity in my science experiment to measure the frequency (or the pitch, I haven't really decided) of a sound, but I can't figure out how to go about understanding the information. I have the recording thing down pat, it's the analyzation that throws me off. I don't know how to get the program to tell me one number that is the frequency of the note. I know that many pitches have multiple frequencies, but I need some way to be sure of the numbers that I am getting. I have tried internet tutorials, but they aren't helping at all. I just need someone to tell me what all these terms mean. Please help!!!

Thanks,
hurleyan

Are you working on the experiment: "Less Cowbell!" https://www.sciencebuddies.org/science- ... p040.shtml

If so, I know some of the creators of that experiment. I'll see if I can get one of them to help answer your question.

Well, no natural sound will really be just one frequency, but you can find out the ones that are strongest by selecting the sound and clicking "Analyze->Plot Spectrum". That's a good overview, but it's kind of hard to get precise information. Select 16384 to get the highest precision, and click on "Export". It will save a file containing the sound level at a lot of various frequencies. Look for the highest few (remember that negative numbers are higher when they are smaller in magnitude).

Hope that helps.

Here's some additional help from one of the creators of that experiment:

"I would suggest starting with frequency and converting to pitch if your project warrants it. Audacity seems to be frequency-friendly. As far as I can tell, there are no direct outputs that says "frequency is such-and-such." You've got to use the tool to measure the frequency, and harmonics if applicable (if there's anything but a sine wave).

First, highlight the waveform you are analyzing. Make sure it's at least a second or more of data. Next select the Analyze pulldown and click on Plot Spectrum. Another window will appear showing the spectrum or frequency-axis of the waveform -- including harmonics. You may want to experiment with Size (8192 is good) and also go to Log Frequency on the Axis. Each peak and associated amplitude is the frequency content of your signal, with the leftmost and largest component being your fundamental frequency."

Good luck.