Autodesk 64006-051108-9001 User Guide - Page 89

The Audio Tab 81 Use the Dynamic Range filter in conjunction with the Volume adjustment. The Dynamic Range is applied first, then the volume is modified, which enables you to encode both ends of the range of the audio, then increase or decrease its total volume. For example, you can limit the Minimum to 20% and the Maximum to 90% for a very narrow dynamic range to make sure the limited audio is as loud as possible without distortion. Experimentation is the key to finding the best settings given your material and preferences. Custom Dynamic Range Settings The Dynamic Range filter Custom option offers three sliders: •Minimum Amplitude - controls how the quiet portions of the signal are modified. Zero leaves the low volume sections unaltered. Higher settings increase the loudness of the previously quiet sections. •Maximum Amplitude - alters the volume of the loud parts of the audio. The numbers on this slider represent the percentage of maximum original volume, which is the same as the Adjust Volume slider. A setting of 100 leaves the loud portions unaltered, and settings below 100 reduce the volume of these portions. •Lookahead - controls how far in advance of the current sample the Dynamic Range filter analyzes to determine how to modify the current volume. Longer lookahead values create smoother transitions between altered and unaltered sections of the audio. Smaller values create shorter and potentially noticeable transitions between sections of the audio. Very small values may make the audio sound choppy. Noise Gate The Cleaner Noise Gate filter completely silences sections of the audio that are very quiet (but not silent) for a period of time. This is useful for material like narration, which should be totally silent between sections, but may have background noise. In addition to Mild, Moderate, and Extreme presets, you can choose a custom setting. Using the Noise Gate filter is especially helpful in conjunction with variable-bitrate audio codecs, such as Qualcomm PureVoice, when used for low-bandwidth streaming. This is because totally silent sections take less bandwidth with variable-bitrate audio codecs. Therefore, proper use of the Noise Gate with appropriate material can reduce the overall size of the audio file. Note: The Noise Gate filter is also sometimes referred to as a Clamp filter because it clamps down on the signal below a certain threshold.