Resurfacing Records to Sound Good Again
Final Updated on May 4, 2021
Y'all finally got your ring into the studio to lay down some tracks. Perhaps you're a product sound mixer, and have only finished weeks of a gruelling film shoot. Maybe you lot completed a field recording session of roaring race cars.
Then, when you load the tracks into your editing app, you find a problem. Maybe in that location's fizz on the guitar track. Perhaps the main grapheme'southward dialogue is soaked with hiss. You realize you lot prepare your levels too high and the stock car passes by have peaked.
It's a frustrating experience to realize recordings captured on location are filled with problems. After all, it's not piece of cake to tape the same audio once again. Oftentimes, it's incommunicable.
Not to worry. Today'due south article is here to aid. It shares 4 tips to repossess and improved damaged audio.
Repairing Audio Problems
Information technology's not easy to capture completely pure sound recordings. Sound issues tin occur from simple homo errors , such as setting levels improperly, misaligning microphones, and more. Often ecology issues occur that harm fifty-fifty the most prepared sessions: noise, RF interference, rumbles, and whines.
While annoying, sound issues like these are normal. Because of this, software has been designed to ready them. Nigh of the fourth dimension these have the shape of audio plug-ins used in tandem with editing software like Nuendo, Pro Tools, and Reaper. These plug-ins select slivers of problematic audio and prepare them piece by slice.
Of form, it'due south more circuitous than clicking a single button. Often sophisticated controls are used to tweak the settings for the finest control. Often this practise of audio restoration is a diligent, difficult, and fourth dimension-consuming process with one goal: repair problems equally transparently as possible.
Why is audio restoration so tricky? Well, making damaged audio sound completely immaculate isn't like shooting fish in a barrel. It'southward like repairing a shattered drinking glass; yes, you can glue the shards back together once again, but the result won't exist the same every bit an unbroken glass. The goal is to repair sound every bit all-time as possible, however, it is nearly impossible to brand a sound appear completely undamaged. Merely like seeing cracks in a glued tumbler, frequently there are subtle problems with audio even after its repaired. And so, fifty-fifty the all-time software or techniques risk creating what is known as artifacts .
With time, patience, and careful listening, damaged audio tin be repaired and artifacts reduced to imperceptibility.
Allow'south have a look at common sound issues and learn how to ready them:
- Clipping.
- Dissonance.
- Rumble, bumps, and mic motility.
- Hum, buzz, and whine.
Clipping
What Is It?
Clipping is a mutual audio problem where the top of a waveform is flattened or "clipped off". While this smushed waveform is easy to spot, the real trouble isn't the way it looks: instead, it indicates damaged audio.
How Does information technology Happen?
Clipping usually happens when recording levels are gear up too loftier, or when sounds are excessively loud (e.k., fighter jets). When loud sounds are captured with these "hot" proceeds levels, recorders are overloaded, so to speak. They cannot handle the loud input. Instead, they capture what they tin can, and cut off what they cannot. The event? The loud sound is "clipped", and missing part of the audio.
Why is it a Problem?
Clipped audio sounds nasty. Often it has a distorted or saturated audio to it. Beyond this unpleasant sound, clipping ways that sound is not captured completely. The loudest part of the betoken is lost, and not recorded at all.
How to Ready It
Thankfully, there are a few plug-ins that help. They work by looking at the sound on either side of the clipped section, and use that to recreate the damaged audio. In most cases, steps include selecting the damaged area and specifying how much the level should be reduced.
Plug-In Options
Check out iZotope RX or Accusonus' ERA De-Clipper to repaired severed audio.
Noise
What Is Information technology?
Racket is ane of the biggest problems experienced when recording audio. It is an airy, hissy sound that appears throughout recordings.
How Does it Happen?
Racket is everywhere. Y'all can hear it from fans and air conditioners. Big spaces are naturally noisy. For those recording outside, subtle air current can add a troublesome hiss to tracks. Every microphone, preamp, and recorder adds a tiny bit of noise, and low-quality gear adds more of it.
Why is information technology a Trouble?
Simply similar static on a television, dissonance is unpleasant to hear. What's more, racket competes with the good sound in recordings. It is broadband , significant it can occur in every audio frequency. That means information technology tin overlaps bass grooves, dialogue lines, and wilderness fx recordings.
How to Fix It
Noise is tricky to remove. It is interlaced with adept audio. That means removing information technology risks taking the practiced with the bad.
Here are iii means to remove noise:
- EQ. Utilize equalization to curlicue off the loftier-frequency hiss. Set a low pass filter at a high frequency and gradually reduce it until you hear it robbing as well much of the skilful audio.
- De-Racket Plug In. Dissonance reduction plug-ins work by sampling sections of pure dissonance (i.e., without good audio) known as a noise profile , and using that as a template for what to strip from the recording.
- Multi-ring Compression. It's a scrap more work, but multi-band pinch can oft reduce noise. It'south done by soloing each ring, setting the threshold for the dissonance level, so reducing the gain so it disappears. Discrete ring controls customize how much noise is stripped from each band.
With all de-noising, it's important to careful: removing likewise much strips the life from recordings at best, or adds subtle, tinkling robotic glitches at worst.
Plug-In Options
There is a broad range of racket removal plug-ins: Accusonus ERA Noise Remover , iZotope RX , Waves X-Dissonance , Z-Racket or Noise Suppressor , Antares SoundSoap 5 , Sonnox Oxford Denoiser , and others.
One popular multi-ring compressor is Waves C4 .
Rumble, Bumps, and Mic Movement
What Is Information technology?
Sometimes you'll hear rumbling in recordings. It may exist a constant low-finish growl. It could be a momentary thump. Whichever the case, information technology's conspicuously not part of the practiced audio in your recordings, and must be removed.
How Does it Happen?
Low-end rumble comes from a number of sources. Sometimes subtle wind or afar traffic can add together low-finish energy to outside recordings. A short thump may occur from moving a microphone, or jostling it in a stand.
Why is it a Problem?
This bass rumble causes a few problems. Constant rumbling makes a audio appear "muddy", washes a sound with low-end energy, and steals definition from the recording. Momentary bumps are distracting, and may overwhelm other frequencies of sound.
How to Set up It
This problem is easy to fix. Set a loftier-pass EQ filter around 100 Hz with a slope of 12 dB. Discover a balance between removing the rumble and taking abroad too much of the good sound with it.
Momentary sounds tin exist stock-still past using spectral repair lassoing tools to sculpt out the bump, replace it with other audio, or remove it from the rest of the frequency.
Plug-In Options
Whatsoever equalizer tin can be used to apply a high-pass filter to rumbling audio. Fab Filter'south Pro-Q 3 is a community favourite. You can use iZotope RX's Spectral Repair to "pencil out" intermittent bumps.
Hum, Fizz, and Whine
What Is It?
Hum, buzz, and whine are exactly what you'd look from their names: consistent gritty or nasal tones that persist through recording.
How Does information technology Happen?
Prepare your recorder too close to an electrical panel box? Maybe your microphone is beneath a fluorescent lite. Mayhap there'due south a afar HVAC unit. Any of these can contribute whines, buzzes, or hums. Oftentimes they're imperceptible, and won't be heard until you're in the edit suite, later on.
Why is it a Problem?
Hums and whines are stubbornly intrusive. They invade not simply ane frequency, but multiple harmonics throughout the audio spectrum. Of course, this overlaps the good audio you lot want to keep, and conveys a grungy sound that must be removed from any audio.
How to Fix It
The expert news nearly buzzes and whines is that they oftentimes occur at predictable fundamental frequencies based on the alternating current mains electricity . This volition exist either 50 or 60 Hz, depending on the country. So, the strongest hum will occur at that frequency (e.g., threescore Hz), and a number of frequencies higher up information technology (due east.g., 120 and 180 Hz, and so on).
Target these frequencies using an EQ notch filter . That will narrow in on simply that frequency without harming the ones around it. Augment or narrow this Q to strip out the hum without affecting other sounds, and do the aforementioned for other harmonics equally well.
Some plug-ins do the chore more easily. They intelligently detect the hum and all harmonics of it, and slice them away in i step.
Plug-In Options
Hum removal plug-ins are available from SoundSoap 5 , Absentia DX , iZotope RX , Waves , and others.
Pro-Q 3 or any other notch EQ can do the piece of work manually. McDSP's NF575 can find a hum frequency and automatically link 4 additional harmonics to reduce whine with a footling less piece of work.
You're bound to experience these audio problems at some point during your pro sound career. Don't worry, though, information technology is possible to set them. With time, patience, and a proficient ear, yous'll fix troublesome audio and be back to creating albums, films, and soundscapes.
Source: https://www.soundsnap.com/blog/4-quick-tips-for-fixing-damaged-audio/
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