Viewing a Sonogram

Available only in Sound Forge

What do you want to do?

Generate a sonogram

  1. Select the portion of the waveform you want to analyze. The sound or note you want to analyze should be in the center of the highlighted area.

Analyzing long sections of audio can take a long time and lowers the time resolution, so your selection should be relatively short. Also, if the audio has a low amplitude level, you can boost it by using the Volume or Normalize functions.

  1. From the Tools menu, choose Spectrum Analysis. The Spectrum Analysis window is displayed.

  2. Use the Spectrum Settings dialog to select the frequency and amplitude range you want to see.

You will often have to experiment with different parameters in the Spectrum Settings dialog to get the best graph possible. Try to narrow the frequency and amplitude ranges as much as possible to achieve large contrasts. If the graph is too chunky, raise the Sonogram resolution setting to approximately 200. For more frequency resolution, increase the FFT Size. To decrease processing times, lower the number of samplings or the FFT Size.

Adjust color and intensity

  1. From the Display menu, choose Sonogram (Color) or Sonogram (B&W) to specify whether you want to view a color or black-and-white sonogram.

  2. Drag the slider below the sonogram to adjust the color intensity of the display. The bottom-right corner of the window will show the color scale in dB.

This function may be fairly slow if you do not have a palletized driver or if Video for Windows is not installed.

View frequency and amplitude information

From the Options menu, choose Show Position. As you move the cursor through the sonogram, the amplitude and frequency values at the current position are displayed in a tool tip next to the cursor and in the overview window in the lower left-hand corner of the Spectrum Analysis window:

If you want to display the the nearest musical note equivalent of the cursor position in a tool tip, choose Show Notes from the Options menu.

Synchronize graphs in a stereo file

If you are analyzing a stereo file, choose Sync Graphs from the Display menu to synchronize both displays in a stereo file so you can view the same region of the FFT in both channels.

Use a sonogram to find the fundamental frequency of a sound

  1. Select the portion of the waveform you want to analyze. The sound or note you want to analyze should be in the center of the highlighted area.

  1. From the Tools menu, choose Spectrum Analysis. The Spectrum Analysis window is displayed.

  2. From the Display menu, choose Sonogram (color).

    The sound you want to analyze should be displayed in shades of red. Hover over the center of the area to display the fundamental frequency.

    If upper harmonics exist, they will be displayed as less intense red area above the fundamental, and will usually be multiples of the fundamental (a note at 440 Hz played on an instrument with fairly predictable or even harmonic content will have strong upper hamonics at 880kHz and 1.76kHz).

After isolating a sound's fundamental frequency, you can use equalization to emphasize or attenuate the sound.