Objective: Remove sections of audio tracks with low-level noise, such as hiss or hum. Background: Sonar’s “Remove Silence” DSP function may seem like “just a noise gate,” but it can also reclaim hard drive space because if you define passages as silence, they won’t be stored within a track as audio. This function can also physically remove those parts of a long clip containing silence, thus creating a series of smaller, separated clips.
- Select a Track or Clip, then go Process > Audio > Remove Silence.
- Signals louder than the Open Level parameter value are not considered silence, while signals lower than the Close Level parameter are. Adjust these parameters so that unwanted low-level signals, or actual silence, fall into the silent range.
- Attack determines how long it takes for the gate to open after being told to open, while Decay specifies the amount of time for the signal to continue after the gate closes. A non-zero Hold value guarantees that the gate will stay open for a specific amount of time, regardless of the signal level, while the Lookahead parameter opens the gate before the signal reaches the Open Level, according to the time specified by this parameter. Set Lookahead to a fairly low value to avoid cutting off part of a rising transient.
- To physically remove the silent parts, thus creating multiple clips separated by space instead of silence, check the Split Clips box.
- Check out the results of your parameter settings by clicking on the Audition button. Sonar will playback and repeat a short section of audio.
- If you think you’ll want to use these settings (or a variation on these settings) in the future, create a preset: Enter a name in the name field, then click on the Save (floppy disk icon) button.
- When all is set as desired, click on OK to apply the DSP to the selected Track or Clip.
- In step 2, you can set fairly high open and close levels to create effects like gated drum decays.
- In step 3, Hold is very handy if the gate “chatters” when a signal crosses back and forth over the open/close threshold.
- When stripping lots of small sections, be conservative with your settings (low Open and Close values, a couple hundred milliseconds of hold time, no attack, a dozen milliseconds of lookahead time, and about 250 ms of decay) to make sure you don’t remove anything you want to keep.
- If you remove silence in an entire track, listen to the track to make sure all is well before it’s too late to hit undo.