Peak levels

160

Normalize to

This fader specifies the level to which the highest peak should be set.

•With Peak level, if the peak level is -10 dB and the Normalize to value is -3 dB, a constant boost of 7 dB is applied to the entire file.

•With Average RMS power, normalizing to 0 dB means boosting the signal until it has the same apparent loudness as a 0 dB square wave. This results in all the dynamic range of the signal being flattened and all peaks being either clipped or seriously compressed. For more information, see If clipping occurs on page 161.

Note: As a rule, normalizing usingto 0 dB is acceptable, but normalizing using Average RMS power to anything above -6 dB is not recommended.

Scan settings area

The controls in this area allow you to determine the response of the RMS power scan to the dynamics in the file.

•The Ignore below fader determines the level of audio data included in the RMS calculation. Data below the threshold is ignored, effectively eliminating silent sections from RMS calculation. The Ignore below fader should be set a few dB above perceived silence. If Ignore below is set to -Inf., all audio data is used.

However, if the value is set too high (above -10 dB) the RMS value may never rise above the threshold. In this case, normalization cannot occur. For this reason, you should evaluate the threshold by clicking the Scan Levels button. For more information, see Scan Levels on page 160.

•The Attack time value determines how quickly the scan responds to transient peaks.

•The Release time value determines how quickly the scan should stop using transient peak material after it begins to drop in level. Slower release times result in more data being included in RMS calculation.

•Selecting the Use equal loudness contour check box allows the scan to compensate for the Fletcher-Munson Equal Loudness Contours. The Fletcher-Munson Equal Loudness Contours illustrate that very low- and high-frequency audio is less perceptible to the human ear than mid-range audio. Therefore, selecting this option forces the scan to factor this into RMS calculation.

Scan Levels

Clicking Scan Levels initiates Peak and RMS scans on the audio and displays the RMS level and the highest peak level detected. When previewing a normalize effect, the entire file must be scanned to preview a even small selection. Clicking Scan Levels saves the current Peak and RMS values and allows you to preview different Normalize to settings without re-scanning the entire file.

Current Peak and RMS levels

An asterisk adjacent to a level value indicates that the value is not current. This occurs when the selection is updated or the dialog is initially opened. To update values, click Scan Levels.

Noncurrent Peak and RMS levels

PROCESSING AUDIO

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