Audio Clipping

What Is Clipping?

In audio, “Clipping” occurs when you push the speakers beyond their capabilities. This is sometimes referred to as overload. The reason why this is happening is that there is no limit to the amount of power that is supplying the amplifier inside the speaker. A typical wave looks like a “ Sinewave “ with smooth edges. After sound clipping, the wave transforms into the “Square Wave“. This results in sound distortion. Aside from that, types of clipping can be hard, soft, and limiting.  

Hard Clipping

It is mainly found in the digital audio domain and can be explained as follows: Your DAW measures volume levels using a system of decibels relative to full scale (dBFS). 0dB is defined as the topmost point of this scale. It’s as loud as anything can go without becoming distorted. If you push the gain of an audio source up so that its amplitude goes above this 0dB point, the DAW will “clip” off the top portion of the audio’s waveform. For example, the curved top of a sine wave will be flattened down into a straight horizontal line. This will make it look and sound much more like a square wave. The abrupt juncture between the normal waveform, the clipped portion, and the high harmonic frequencies can make the audio sound extremely harsh and fuzzy.  

Soft Clipping

This is a milder distortion, and you can use it as a creative effect on an audio signal. Its timbre is often much less harsh than hard clipping. Soft clipping results in increasing input amplitude related to gradually increasing distortion. This is due to the increasing deviation of the shape compared to the original input. There is also potential to change the soft clipping transfer function shape to achieve a range of slightly different distortion characteristics. Compared to the hard clipping, it avoids this harshness by gently transitioning between the unclipped section of the waveform and the clipped section. When you apply soft clipping to a sine wave and then look at a visual representation of the waveform, the junction between the normal, curved portion of the wave and the flat, clipped portion looks curved. Although there’s still distortion, it’s much less harsh-sounding than it would be if you hard-clipped the signal. It generates fewer high-pitched harmonics than hard clipping does. The gradual transition to the clipped part makes the audio sound much smoother and warmer.  

Limiting

Limiting is an altogether much more controlled audio process. Here, a loud signal is briefly attenuated, specifically to avoid clipping. The short-term dynamic changes involved introduce a form of distortion, but it is a far more benign form, and, again, it is rarely recognized as such. The system is linear up to the limiting level, above which the waveform reduces in amplitude but more or less retains its original shape and thus remains harmonically intact. The distortion that results is usually negligible.