How Does Clipping Happen?
When clipping occurs, instead of a smooth sine wave being produced as with normal audio, a squared-off and “clipped” waveform is produced by the amplifier, resulting in sound distortion. Similarly, in digital audio, there’s a limit as to how far an input sound can be represented. If the amplitude of a signal goes beyond a digital system’s limits, the rest of it is discarded. This is particularly bad in digital audio, as a large amount of definition can be lost through audio clipping.
Effects of Clipping
Audio clipping can be hard, soft, or limiting. Hard clipping delivers the most loudness but also the most distortion and loss of bass. Soft (also called analog) clipping delivers a smoother sound with some distortion. Limited clipping distorts the least, but it reduces the loudness the most, resulting in a loss of punch. Not all clipping is bad or unintentional. For example, a hard-driving electric guitar player may intentionally induce clipping through an amp to create distortion for musical effect. In most cases, however, clipping is an undesirable result of incorrect settings or audio equipment that is of poor quality or simply not up to the demands being placed on it.
Eliminating Audio Clipping
Prevention is always better than a cure, as the saying goes, and that applies to clipping, too. It’s advisable to record digital audio while keeping the input signal within limits. However, if you have digital audio files that you need to improve, use certain audio tools to attempt to eliminate clipping as much as possible. Examples of audio software that can do this include:
Software media players with normalization: Some jukebox software players such as iTunes and Windows Media Player have built-in normalization features to process audio files that can prevent songs from being clipped. Standalone normalization tools: Third-party audio tools like MP3Gain can normalize the tracks in your music library. These tools adjust the loudness of songs to play at the same volume and reduce audio clipping. Audio editors: These programs provide many ways to digitally process an audio file. Audio editors such as Audacity have advanced algorithms to permanently remove clipping. ReplayGain: Similar to software tools like MP3Gain, this feature is built into some MP3 players. ReplayGain metadata can be useful for preventing loud songs from being clipped by the hardware’s internal digital-to-analog amplifier. CD/DVD-burning software: Disc-burning programs often come with an option to normalize tracks, especially when creating audio CDs for playing on home entertainment equipment.
