What function does a limiter serve in audio processing?

A limiter is an essential tool in audio processing that serves to manage the dynamic range of a signal. Its primary function is to restrict the signal level, ensuring that audio does not exceed a specified threshold to prevent clipping, which occurs when the signal level surpasses the maximum it can handle. Clipping can lead to distortion and undesirable sound quality, particularly during loud peaks in the audio.

By employing a limiter, audio engineers can maintain a more consistent signal level, allowing for brighter and louder mixes without sacrificing clarity or introducing distortion. This function is critical in both live sound reinforcement and studio mixing when controlling peaks to keep audio outputs within safe limits, thereby preserving the integrity of the sound.

The other options presented do not accurately describe the primary function of a limiter. While boosting signal levels, balancing frequencies, and softening high frequencies are important aspects of audio processing, they are specific to other types of audio tools and do not align with the primary role of a limiter.