Limiter Stereo

Begrenzer Stereo

Detailed: LSP Limiter Stereo (B1S)


Categories: Limiter

Developer: Vladimir Sadovnikov


This plugin implements a limiter with flexible configuration. In most cases it acts as a brick-wall limiter but there are several settings for which is acts as an compressor with extreme settings, so the output signal may exceed the limiter's threshold. It prevents input monosignal from raising over the specified Threshold.

Attention: this plugin implements set of limiting modes, most of them are iterative. That means that CPU load may be not stable, in other words: the more work should be done, the more CPU resources will be used. Beware from extreme settings.

The gain reduction algorithm is split into two stages:

Simplified peak processing example is shown on the following picture:

Simplified peak processing example

Of course, the output signal does not repeat the envelope form of input signal because it's amplitude is changed smoothly, so in fact the form of output signal is more complicated.

Currently there are three forms of patches applied to the gain curve - hermite (using cubic polynom for interpolation transients), exponential and linear. These forms can be explained with following picture:

Forms of patches applied to signal

Gain reduction patch affects not only the peak sample, but also surrounding samples. The position and form of this interpolation is related to the peak, so there are four different variants of patch envelope - thin, tail, duck and wide. All these forms related to the peak are shown on the following picture:

Envelope forms of the patch

On this image, sloping lines mean the transision part of the patch. The flat cap in the middle before the peak is a half of attack time, the flat cap in the middle after the peak is a half of release time. Also it's obvious that different envelope forms differently affect dynamics of the signal.


'ALR' section:

'Limiter' section:

'Signal' section: