Viewing a Spectrum Graph |
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In the Spectrum Analysis window, the Spectrum Graph displays the amplitude (in dB) of each frequency component from 0 Hz to the Nyquist frequency.
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.
From the Tools menu, choose Spectrum Analysis. The Spectrum Analysis window is displayed.
Use the Spectrum Settings dialog to select the frequency and amplitude range you want to see.
You
can continue to make selections in the sound file with the Spectrum
Analysis window open (just move the cursor or make selections as you
normally would in Sound Forge). Click Update!
from the Spectrum Analysis main menu bar to update the spectrum
display (or choose Auto
Update from the Options menu). If no selection is made,
analysis is performed on the samples immediately following the cursor position.
As you move the cursor through the Spectrum Graph, the amplitude and frequency values at the current position are displayed in the overview window in the lower left-hand corner of the Spectrum Analysis window:
From the Options menu, choose Show Position to display amplitude and frequency information in a tool tip next to the cursor:
To focus on a specific amplitude or frequency range, use the Zoom tool to change the focus of the graph.
If
you want to display the nearest musical note equivalent of the
cursor position in a tool tip, choose Show
Notes from the Options menu.
From the Display menu, choose Line Graph, Bar Graph, or Filled Graph to change the type of graph in the Spectrum Analysis window. A check mark is displayed next to the selected graph type.
Some
video drivers have problems displaying in Filled Graph mode. If you
encounter problems such as incorrect shading or very slow drawing,
use the Line Graph
or Bar Graph
options or change video drivers.
Zooming can be accomplished in several ways:
Drag on the graph and draw a box around the area where you want to zoom. You can toggle through mouse selection mode by right-clicking while holding the left mouse button:
The first type is a vertical zoom window. This will allow you to zoom into a frequency range.
The second type is horizontal zoom window. This will allow you to zoom into an amplitude range.
The third type is a combination of vertical and horizontal zoom. This will allow you to zoom into a frequency and amplitude range.
From the Display menu, choose Zoom to Range to set the amplitude and frequency range to the maximum and minimum values specified in the Spectrum Settings dialog.
From the Display menu, choose Zoom Out Full to view the entire amplitude and frequency range.
From the Display menu, choose Normalize dB to set the Spectrum Graph amplitude range equal to the maximum and minimum values in the graph.
If you are zoomed into a selection of the spectrum graph, choose Grab/Pan
from the Display menu. The cursor will be displayed as a ,
and you can drag horizontally or vertically to scroll through the graph.
When you are zoomed into a selection of the spectrum graph, you can drag the horizontal and vertical sliders to scroll through the graph.
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.
From the Options menu, choose Print to send the contents of the Spectrum Analysis window to your printer.