Difference Between Limiter and Compressor

Limiter vs Compressor

Limiters and compressor are dynamic processor components used in audio mastering and recording. A limiter limits the sound level and the compressor increase the compactness of the sound. Their primary function is keeping volume levels below a predetermined level in recording studios.

More about Compressor

A compressor is a component that reduces the dynamic range of the audio signals, effectively reducing the range between the loudest and the quietest noises in the audio signals. This is achieved by attenuating the louder signals and amplifying the quieter signals.

In the compression process, following factors are considered and changed.

Threshold : the upper limit of the loudness before the compression is applied.

Compression Ratio: the degree of compression to be applied. For example, if the compression ratio is set as 8:1, the output signal is only one eighth of the input signal.

Attack : the speed of response to the compressor.

Release: the delay for the signal to drop after reaching the threshold.

Knee: the nature of the reaction after the threshold is reached by the input signal.

Hard Knee – clamps the signal straight away,

Soft Knee – compression starts gradually as the signal develops further past the threshold.

Make-up Gain: since the compression attenuates the signal this feature allows you to amplify the signal to compensate the loss of the signal strength.

The main types of compressor used in audio mastering and recording are VCA, Opto (optical), FET, and valve compression techniques.

More about Limiter

Limiters, rather than reducing the band from both ends of the signal loudness, act only in the louder region of the band. As the name implies, its purpose is to limit the signal when reaching a determined level by attenuating the signal. Simply it creates an upper limit for the sound level, but no lower limit.

From one perspective, a limiter can be seen as a one end compressor, therefore, is a subset of compressors. Hence, all the limiters are compressors, but not all the compressors are limiters. Limiters are used in severe reducing actions and acts as overload protection too. Also, limiters have faster attack times and release times, therefore, has the ability to respond to sudden, transient peaks without affecting the quality of the signal.

What is the difference between a Compressor and a Limiter?

• A compressor is used to shrink the dynamic range of the sounds by reducing the lowest and the highest sound levels, while limiters only consider the highest sound levels.

• Limiters have faster response time and release times.

• Limiters are used for overload protection, while compressors are used for more subtle artistic alterations.