Limit¶

The Purpose of a Limiter¶

Limit is a two-stage dynamic processor, designed to transparently increase the perceived loudness of audio, while at the same time making sure no audio clipping occurs. First, there is a compressor stage (Pre-Compressor) that helps to keep the number of exceeding peaks within an acceptable range, which helps to prevent or reduce audible distortion. The second stage is the actual peak limiting stage (Peak Suppression) which makes sure that no audio will pass through above the threshold, also known as brickwall limiting. In this stage, peaks are reduced with a very quickly responding algorithm in the most transparent way as possible.

User Interface¶

Limit UI

Parameter Settings¶

Input (0 dB to +32 dB)

The internal threshold in Limit is always 0 dB. In order to increase the perceived loudness, you need to increase the input level of the audio. As soon as the input audio will exceed the internal threshold, gain reduction will be applied in order to keep the audio from clipping. Excessive amounts of gain reduction can lead to audible distortion and/or a pumping effect. For mastering duties, we recommend to keep the amount of gain reduction to a minimum.

Output (0 dB to -32 dB)

The output of Limit is set to 0 dB by default, but can be used to compensate for the increased level when the input is boosted.

Attack time (0.01 ms to 500 ms)

You can use the attack time knob to adjust how quickly the Pre-Compressor stage will react to incoming audio that is above the internal threshold. The faster the attack time, the faster the compressor will react. A fast attack time will be more transparent, at the cost of a slightly lower increase in perceived loudness. A slow attack time will increase the perceived loudness, at the risk of introducing audible distortion or a pumping effect.

For mastering duties, we recommend to start with an attack time of 40 ms and adjust it to taste.

Release time (1 ms to 5000 ms)

You can use the release time knob to adjust how quickly the compressor will stop processing audio that is no longer above the internal threshold. A fast release time will greatly increase the perceived loudness at the risk of audible distortion. A slow release time will be more transparent, at the cost of a lower increase of perceived loudness.

For mastering duties, we recommend to start with a release time of 150 ms and adjust it to taste.

Auto-Release button

You can enable auto-release mode by clicking the button labeled "A" on the left side of the numerical entry field for the release time. In auto-release mode, the release time specifies the maximum release time and the pre-compressor shortens the release time for sharp transients.

Pre-Compressor Channel Linking (0% to 100%)

With the channel linking set to 100%, the amount of gain reduction will be the same for the left and right channels, even if there is a difference in level between these channels. The more you dial the knob away from 100%, the more the channels will be independently treated, with complete independence between the channels once you have a 0% channel linking. Channel linking values below 100% can result in shifts in the stereo image.

During mastering, the best results will be most likely achieved with the channel linking set between 70% and 100%.

Look ahead time (0 ms to 30 ms)

Limit uses a sophisticated look ahead algorithm to ensure the highest possible transparency. The higher this value, the more transparent the processing will be. Please keep in mind that look ahead time will also introduce latency, which will normally be automatically compensated for by your host application.

Peak Suppression Channel Linking (0% to 100%)

With the channel linking set to 100%, the amount of limiting will be the same for the left and right channels, even if there is a difference in level between these channels. The more you dial the knob away from 100%, the more the channels will be independently treated, with complete independence between the channels once you have a 0% channel linking. Although channel linking values below 100% can result in shifts in the stereo image, it is not as evident as during the pre-compressor stage.

During mastering, the best results will be most likely achieved with the channel linking set between 50% and 100%.

Oversampling (off, 2x, 4x)

The internal sample rate of Limit can be multiplied by 2 or 4, depending on the sample rate of the project. For example, if you have a project with a sample rate of 48 kHz, setting the oversampling to 4x will result in an internal sample rate of 192 kHz.