Limiter
Functionality
The Limiter prevents your signals from raising over a desired thershold. The Calf limiter makes up your audio signal automatically by the threshold set.
This limiter uses lookahead technology to prevent your signal from distorting. It means that there is a small delay after your signal is processed. Keep in mind that the delay it produces is the lookahead time you set.
Controls
- Input (knob): Raise the volume before the signal is sent in the compression stage. If you have found some great settings but want to raise the overall loudness of the track simply increase this level.
- Input L/R (VU-meter): The level of the original signal
- 0dB (LED): Flashes if the level of the original signal raises above 0dB (it doesn't clip your signal)
- Output L/R (VU-meter): The level of the compressed and made up signal
- 0dB (LED): Flashes if the level of the output signal raises above 0dB (it may clip your signal depending on your host and your systems' bitrate!)
- Output (knob): Raise the overall volume after the compression stage
- Bypass: Don't process anything, just bypass the signal
- Split: Frequency to split between these strips
- S: Separate or overlap the frequencies of the neighbour bands
- Q: Raise the center frequency
- Limit: Don't let signals above this level pass the limiter.
- Auto-level: If enabled, scales the output signal to 0 dBFS, effectively applying a gain equal to the inverse of the limit setting - adding back the removed amplitude in the process.
- Lookahead: The Limiter will reach its attenuation level in this amount of time (output will be delayed two times this time)
- Min Release:Don't let the release time fall beneath 2.5 times the lowest possible wavelength per band
- Release: Come back from limiting to attenuation 1.0 in this amount of milliseconds
- ASC: When gain reduction is always needed ASC takes care of releasing to an average reduction level rather than reaching a reduction of 0 in the release time
- ASC Level: Select how much the release time is affected by ASC, 0 means nearly no changes in release time while 1 produces higher release times
ASC: Adaptive Slope Control
The release time is the time needed to return from possible gain reduction after a peak appeared back to no reduction.
Now let's look at the case when permanent gain reduction of e.g. 6dB appears. If a peak appears in this situation the release time would be calculated to reach zero. Since it isn't able to go back to no reduction (because on average it just goes back to the permanent 6dB) the time for the release would on average be shorter than set by the user. That's what ASC is developed for.
It keeps track of the average gain reduction (in fact it keeps track of the average signal strength, but for this explanation seeing it as reduction is easier for understanding) and takes this as the final state of the reduction while calculating the release slope.
The LED displays when the ASC slope is used instead of the normal one. This happens if the ASC slope is smaller than the normal one.
The value of the ASC Level knob sets the amount of the ASC slope before the comparison. The higher this value is set the more often the ASC slope is used instead of the normal one. This results in a temporary higher release time for this peak, if releasing back to no reduction.
(The image doesn't care about logarithm)
This results in a much softer limiting with more smooth release processes whatever material is stuffed in there. A little less loudness but audibly less distortion. If only few peaks happen while the limiter isn't doing anything most of the time, enabling ASC doesn't affect the limiting process. It only hits in as soon as there is permanent gain reduction and evens it out, that's why it is enabled by default.