What is Aliasing (Audio)?

Aliasing is a type of digital audio distortion that occurs when a signal contains frequencies higher than half the system’s sampling rate. When this happens, those high frequencies cannot be represented correctly and are reflected back into the audible range as incorrect or unwanted tones.

In digital audio systems, sound is captured or processed using a specific sample rate, such as 44.1 kHz or 48 kHz. According to the Nyquist theorem, the highest frequency that can be accurately represented is half the sample rate. Any frequencies above this limit can create aliasing artifacts.

Aliasing often appears as unnatural, metallic, or inharmonic tones that were not present in the original signal. These artifacts are especially noticeable in heavily processed sounds such as distortion, saturation, digital synthesis, or aggressive pitch manipulation.

To reduce aliasing, many audio systems use anti-aliasing filters that remove frequencies above the Nyquist limit before processing. Another common solution is oversampling, which temporarily increases the internal sample rate so that new harmonics generated by effects remain within the valid frequency range.

Aliasing is an important concept in digital sound design and audio engineering. Producers often manage or prevent it when working with synthesizers, distortion plugins, and digital processing tools inside digital audio workstations such as Ableton Live, FL Studio, and Logic Pro.