What Is Clipping? – And How To Prevent It While Recording
We all heard this many times before. A commentator gets overexcited during a game on television when a goal is scored and starts screaming, or you turn up the volume of your car audio system to its maximum - both resulting in a screechy harsh distorted sound exploding from the speakers. This brings me to the question which many users new to home recording often ask: What exactly is clipping?
Clipping is a type of distortion in the sound waveform that occurs when an amplifier is driven too far beyond its maximum output capacity by a much higher voltage or signal. The resulting harsh and distorted sound is called clipping.
Understanding what clipping is, already helps. I think it is necessary to really find out why exactly this happens though, so that we can all better understand it and know how to avoid it.
Why Does Clipping Occur?
First, it is important to note that clipping does not happen due to an overload of just an amplifier's capacity, but in many cases a speaker or studio monitor as well. Both have a certain capacity with which they can handle the signal strength, and once this capacity is surpassed by a stronger signal strength, clipping can occur.
The best way to describe how clipping occurs, is by looking at the sound signal as sine wave.
In the diagram above, the dynamic range of the amplifier (recording device) is indicated in green, and the minimum and maximum limits of the dynamic range are indicated by the red lines. The blue wave represents the actual sound wave and strength.
The blue wave stays within the green area, so no clipping will occur as the signal strength stays within the dynamic range of the amplifier.
In the diagram above, the signal strength (blue line) exceeds the capacity of the amplifier's dynamic range (green area) and cross the minimum and maximum threshold (indicated in red). As a result some clipping will occur.
The parts of the sound wave outside the red lines will be clipped. It is during this part where you will normally hear the harsh distorted sound.
This is a fairly simplistic explanation for a more complex situation, but in principle exactly how clipping occurs when an amplifier or speaker is overloaded.
Not all forms of clipping are the same. The two most important forms of clipping are referred to as analogue (or soft) clipping and digital (or hard) clipping.
As the name suggests, soft (analogue) clipping takes place when an analogue system's capacity is exceeded. The transitional sound is very brief and fairly smooth. Sometimes analogue clipping may be so subdued that it can almost be inaudible.
On the other hand, hard (digital) clipping takes place when a digital system's dynamic range is exceeded. This form of clipping is a lot more abrupt and disruptive. As a result the sound produced is much louder and harsher noise than experienced during analogue clipping.
(A third form of clipping, called limited clipping should also be mentioned. This is not an unintentional result of signal overload though. This is a more controlled process where the loud signal is very briefly reduced to avoid clipping. Even though some form of clipping technically still occurs, it is so short and harmless that it can't even be picked up by the system or heard by the listener.)
What Can Be Done To Prevent Clipping?
The first and most obvious way to prevent clipping from happening is to carefully monitor your recording levels. Basically all audio software have onscreen meters showing the level at which the source is being recorded. It is normally color-coded, with green, orange and red indicators.
The green indicates that the recording is taking place within the "safe zone" where the signal strength is not too loud. When the peak signal strengths starts jumping into the orange, it is an indication that volume may be peaking close to the limit of the recording device.
Red is a very clear signal that your signal strength is too strong. If the volume is peaking in the red on a regular basis, clipping is a big possibility and you need to reduce the the gain of your amplifier. By turning the gain down until the peak signal strength is not surpassing the yellow indicators, you will prevent clipping from taking place.
Alternatively, there are plugins available for the majority of popular DAW software to deal with clipping. Mostly this only deals with the effects of clipping once it already occurred. Although helpful, it is not nearly as effective as stopping clipping from happening in the first place.
There is a much more practical way of preventing clipping though. A common mistake that many artists make is by placing their mouths or instruments far to close to the microphone.
A dynamic microphone during a live performance may still be a bit more forgiving, but placing your mouth or instrument right up to a sensitive condenser microphone's diaphragm in a studio, is asking for trouble.
Apart from not allowing the natural sound to naturally develop over distance, your microphone also bears the full brunt of your voice. This can very easily result in clipping if you raise the volume of your voice or instrument.
By putting a distance of around 8-12 inches between your condenser microphone and your mouth, you lessen the impact a change in volume has on a microphone. The added space provides some form of buffering where the peak volume can be dispersed and slightly reduced. As a result the danger of clipping will be reduced to some extend.
The best way of preventing clipping though, is by both setting your gain at an acceptable level where the strongest signal will not overload your amplifier or audio device, while at the same time keeping your mouth or instrument at a safe distance from the microphone to further protect against any possible clipping. (The recommended 8-12 inches).
Clipping is problem that can cause a lot of headaches during recording. Luckily, as we discovered in this article, it can easily be controlled or completely eliminated by following a few simple rules. There is no real need to subject yourself to that harsh unpleasant distortion.
I hope the explanation and solutions provided in this article will help you get rid of any unwanted clipping once and for all.
As always, feel free to leave me any comments or suggestions you may have, and I will respond and try and get to them as soon as I can.
Remember to join my Mailing List to be informed whenever a new article is released, and share new developments and helpful hints & tips.
Catch you in the next article and happy recording!