How to Identify Fundamental Pitch in Audacity

Identifying the fundamental pitch of an instrument recording in Audacity is a straightforward process achieved using the built-in Plot Spectrum tool. By isolating a clean, sustained section of audio and analyzing its frequency distribution, you can locate the lowest resonant peak—the fundamental frequency—and determine its precise pitch in Hertz along with the corresponding musical note.

Step 1: Select a Clean Audio Sample

1. Open your audio file in Audacity.
2. Use the Selection Tool (F1) to highlight a sustained portion of the instrument note you want to measure.
3. Avoid the initial transient attack (the strike, pluck, or breath sound at the very beginning) and the decay tail where noise might interfere. A stable, steady section of roughly 0.5 to 1.5 seconds yields the most accurate result.

Step 2: Open the Plot Spectrum Tool

1. With the audio segment selected, click on the Analyze menu at the top of the screen.
2. Select Plot Spectrum... from the dropdown. A new window will appear displaying a graphical representation of the frequencies present in the selection.

Step 3: Configure Settings for Maximum Accuracy

To get an exact reading, adjust the parameters at the bottom of the Frequency Analysis window:

• Algorithm: Set to Spectrum.
• Function: Choose Hanning window or Blackman-Harris window to reduce spectral leakage and sharpen peaks.
• Size: Increase this value to at least 4096, 8192, or 16384. A higher FFT (Fast Fourier Transform) size increases frequency resolution, allowing you to separate closely spaced frequencies and pinpoint the exact frequency in Hertz.
• Axis: Set to Log frequency to display frequencies similarly to how the human ear perceives musical intervals.

Step 4: Locate and Read the Fundamental Peak

1. Examine the graph from left to right. The fundamental frequency (\(f_0\)) is typically the first major, distinct peak on the left side of the spectrum before the subsequent harmonic overtones appear.
2. Move your cursor directly over this first prominent peak.
3. Look below the graph at the information readouts:
   • Cursor: Shows the frequency and musical note where your mouse is currently positioned.
   • Peak: Automatically snaps to the nearest significant peak near your cursor, showing the exact frequency in Hertz (Hz), the corresponding musical note name, and the deviation in cents.

The value displayed in the Peak field represents the exact fundamental pitch of the recorded instrument.