“Audio clipping” is a phrase many musicians will have heard. It often manifests itself as a warning red light in our DAW, audio interface, or speakers. Most of the time, this results in a scramble for knobs or faders to turn off the light. But, what exactly happens when audio snippets are used? What’s more, why is it crucial to comprehend this basic auditory phenomenon?
Defined Audio Clipping
In the most basic sense, audio clipping is a kind of waveform distortion. Overdrive occurs when an amplifier is pushed past its full capacity. Clipping happens when an overdriven signal forces the amplifier to try and create an output voltage greater than its capabilities.
For example, if a loudspeaker is clipping, the phenomena might be heard as distortion or break-up. Overheating may cause harm to a loudspeaker if it is in a clipping state for an extended period of time. Fortunately, many speakers contain built-in safeguards against clipping, such as circuits that operate as limiters.
Since the 1980s, speakers have utilized a “soft-clip” circuit to restrict the signal at the input stage. The soft-clip circuit kicks in when an input signal is 10 dB greater than the speaker’s set maximum, for example, to restrict the signal and avoid clipping.
Clipping from the Internet
A digital system may be overloaded at the input stage to the point of clipping, much in the same way that a loudspeaker can be pushed past its physical limits. We’ve run out of headroom and may be seeing digital clipping when a signal hits 0 dBFS (full-scale) on a meter. This is due to a lack of 1s and 0s in our system’s ability to correctly translate our signal into digital data. Any extra data is ignored, which may lead to digital clipping, which is when a sine wave hits its ceiling and becomes a square wave.
Digital clipping accurately lops the head off our nice sine wave, resulting in severe distortion, but analogue clipping is more forgiving in the way it slices round waveforms into squares.
What are the Consequences of Digital Clipping?
Not nearly as much as it looks. Simply because a signal in our DAW has reached or beyond 0 dBFS, does not indicate it is distorting. It’s better to trust your ears on this one and think of the red meter as a mild caution rather than a sign of something potentially dangerous to your recording. Of course, we’re talking about our channel faders. It might make mixing difficult if the master fader is continuously turning red.
32-bit float processing, which is included in many DAWs, is also worth considering. On the surface, 32-bit processing offers greater headroom–up to 1680 dB of dynamic range against 144 dB for 24-bit processing. With so much headroom, our signal can’t possibly clip, right? In certain ways, yes.
You’ll never clip with 32-bit float processing as long as your audio remains in the DAW. All bets are off once your content leaves the DAW and is transformed back to 16- or 24-bit. If the use of 32-bit floats is in doubt, it’s advisable to err on the side of caution and continue with 24-bit processing.
Major Takeaways (Audio Clipping)
A smidgeon of red here and there isn’t going to damage anything. If your loudspeakers flare intermittently when they respond to peaks in the replayed material, don’t assume that the internal components are failing! However, if the red light remains fixed and substantial distortion is heard, you should reduce your input signal to avoid overheating your speakers. Thankfully, most speakers have built-in safety features that prevent this from happening in the first place. The worst-case scenario often involves a speaker shutting down before it has a chance to overheat and destroy itself.
Don’t be alarmed if your DAW channel faders clip from time to time. If you’re pleased with the overall mix but one ingredient stands out in certain locations, go with your ears first. Is there any audible stuttering in the signal? If the answer is “no,” don’t feel compelled to lower faders or alter plugin settings to prevent the occasional peak.
To avoid audible digital clipping, if you’re hammering your mix buss at 0 dBFS or above, you’ll want to bring everything down. The amount of headroom you should leave on your mix buss varies a lot from person to person. Before mastering, I’ve heard anything from maintaining peaks as low as -10 dBFS to going as high as -3 or less dBFS.
Clipping is, for the most part, simply avoidable and definitely not the misery of any loudspeaker or DAW. Listen with your ears and trust your instincts. When material is clipping excessively, you’ll be able to see, and modest tweaks may cure the issue.