Adobe 22011292 User Guide - Page 121

ADOBE AUDITION 107 User Guide Level Detector The Level Detector determines the current waveform input amplitude, which is used as the input side of the dynamics processor. Here are its components: • Input Gain is added to the signal before it goes into the Level Detector (the section that detects the current level). This essentially "pushes" the graph up or down by the gain given. • Attack Time is applied when retrieving the current amplitude information. Attack Time determines the time in milliseconds that it takes for the processed output signal to reach its specified output volume. If there is suddenly a quiet portion that drops 30dB, it will take "this much time" before the output actually drops to its corresponding volume level. • Release Time is applied when retrieving the current amplitude information. Release Time is the time it takes the end of a previous output level to reach the specified output volume. For example, where the Attack is the time it takes for the start of a pulse to reach the desired output volume, the Release is the time it takes for the end of the pulse to reach the desired level. • Peak mode is a graph interpretation method that is a little more difficult to use than RMS, and is a bit outdated. It equates to the RMS value times two. That is, if the RMS value is -20dB, then the equivalent peak value will be -40dB. This occurs because the RMS value calculated was mapped to a peak sample value for output. This method is available here for backward compatibility. • RMS is a graph interpretation method that more closely matches the way people hear volume. This mode causes the output to be exactly the RMS amplitude that is specified in the graph. For example, a limiter (flat horizontal line) at -10dB causes the RMS amplitude of the result to average -10dB (where 0dB is a maximum amplitude sine wave without clipping). Lookahead Time Lookahead Time is used to handle sharp spikes that may occur at the onset of a louder signal. At times, and for brief instances, these onsets can go beyond the limits of your compressor settings, which may be desirable in certain compression scenarios since it can enhance the impact of, say, a drum hit. However, this is obviously not desirable if you are using limiting in order to reduce the maximum amplitude of the audio. Note: The spikes occur because it takes a little time to determine (the Level Detector's attack value) and react (the Gain Processor's attack value) to the current signal level, so Lookahead Time will actually cause the attacks to start before the audio gets loud, instead of right on top of the transient. Otherwise, with a Lookahead Time of 0, a spike will stay loud until all of the attack times have elapsed. Band Limiting Tab The fields in the Band Limiting tab allow you to specify a frequency range where all dynamics manipulation will occur.