How to Fix Audio: Clipping & Leveling
A Comprehensive Guide on Audio Repair: Clipping and Leveling
In the good old days of analog audio, you could push the volume of your amp past its limits and make it sound cool, a practice known as distortion. Early blues guitarists would boost the volume of their amplifiers until the internal circuitry was no longer able to recreate the sound. Instead, it would come out "fuzzy" or "dirty". This amp clipping at high volume sound, while not being useful in all circumstances, has found a home in modern music as a clipping sound effect. Now, there are all types of effects pedals and plug-ins which recreate this famous sound. Contrary to analog distortion, digital distortion has not been well received. In the digital world, a sound which exceeds the limits has run out of 1's and 0's to be reproduced. At that point, instead of a warm distortion, the listener is met by an abrupt popping noise, known as "clipping".
There are still holdouts in the recording world who remain faithful to their analog roots. So, if you are recording to tape, skip this article and have a happy day. If you are among the vast majority that is recording onto a computer, let's get to the bottom of how to prevent audio clipping.
When you've gotten to the point of adjusting the gain, be sure to adjust it in the correct place to avoid clipping audio. You may have your signal running through an effects pedal, preamp, plug-in, or some other input processing. All of these things have the ability to boost the input signal. An easy way to get a solid result in most cases, is to keep everything in your processing chain at a medium level and then, use your preamp to do the majority of the amplification. Your preamp amplifies much more efficiently because that's what it's designed to do. An example of poor gain structure would be a preamp at a very low setting that is already clipping because of the amount of gain introduced before it in the chain. Likewise, a preamp at full blast that is still not putting out a decent signal needs to be fed a stronger input.
The final piece of advice for setting your gain level during the recording process, is to set the gain using a proper reference point. The volume of your input is not going to be perfectly consistent. Choose your loudest part and set the gain of your preamp to the point where it is far enough beneath the clipping level that you have a little wiggle room, but not too much.
There are moments though, particularly in the loudest parts of recordings, that it's impossible to set levels below the clipping level and momentary clipping occurs even if you already taken proper care of your input gain settings. This is where ERA De-Clipper comes into play. This plug-in, like all the products in the ERA Bundle, relies on algorithms to intelligently detect clips and eliminate them. With ERA De-Clipper, even a heavily clipping audio track can be corrected in very little time which is rare in the post-processing world. This is also incredibly valuable in a situation where do-overs are impossible, or the setting makes correctly adjusting your input gain difficult. As always, do your very best from the start to avoid reaching the clipping level, and leave the rest for post-production.
Now, if you've got the time, it is always recommended to automate the fader of your recorded voice track, to make the output volume consistent. Still, a much simpler method would be to use the Voice Leveler of ERA Bundle. It analyzes your volume levels and raises all other volumes to match the loudest point - a simple approach to audio leveling. By using specialized algorithms, ERA Voice Leveler is able to balance differences in volume and tone. These differences come from speakers not consistently speaking in the same direction or distance from their microphone. So, this software is particularly useful for you Podcasters out there who need a nice, consistent volume for your voice recordings. Dial in your recordings on "Normal" or "Tight" mode for a varied degree of audio leveling. Then, with the single knob, dial in how much processing you want the Voice Leveler to do.