The need to change the playback speed of an audio clip may arise in different situations. You have to speed up or slow down the sound both when eliminating out-of-sync with the video sequence and when creating original tracks. You can accomplish this task using an audio editor program that has filters to work with the speed of the audio fragment.
Necessary
- - Adobe Audition program;
- - sound file.
Instructions
Step 1
Load the audio you want to work with into Adobe Audition using the Open option, Open Audio from Video if you are editing the audio track of a video file, or Extract Audio from CD if you are opening a file from a CD.
Step 2
Specify the section of the loaded sound, the playback speed of which you want to change. To do this, place the cursor at the beginning of the passage, hold down the left mouse button and select a section of the sound wave. If you need to change the entire file that is open in the audio editor, you don't have to select anything.
Step 3
To work with the speed of sound playback in Adobe Audition, you need filters collected in the Time / Pitch group from the Effects menu. If you need to slow down or speed up the sound by a certain percentage, do it using the Stretch filter. The same filter allows you to adjust the duration of the sound for a certain period of time. Its settings window opens with the Stretch (process) option.
Step 4
The default filter settings window opens on the Constant Stretch tab. If you are going to apply the same speed change to the entire passage, this is the tab you need. In the Stretch Mode field at the bottom of the tab, select a change mode. In Time Stretch mode, you can change the speed while maintaining the tone of the sound. Resample mode changes speed and pitch.
Step 5
Adjust the sound change. To do this, you can specify the new file length as a percentage by entering a value in the Ratio field. The original tempo of the sound is taken as one hundred percent. If you need to speed up the sound, enter a value greater than this value. To slow down the sound, specify a value less than one hundred percent.
Step 6
In some cases, for example, when correcting out of sync between audio and video, you need to stretch or shorten the audio fragment to a certain length. This can be done by entering a new sound duration in seconds in the Length field.
Step 7
If you need to change the sound at the beginning and end of a fragment differently, go to the Gliding Stretch tab and adjust the correction for different parts of the file. The initial velocity is set in the Initial panel, and the state of the sound at the end of the edited fragment is determined by the settings in the Final panel.
Step 8
Listen to the result of applying the set parameters by clicking on the Preview button. The edited file can be saved using the Save As or Save Copy As options from the File menu.
