How to Clean Up Audio and Remove Background Noise

Learn more about Audio Cleanup in part 2 of this article.

When do I need to use audio cleanup and noise reduction software?

In today’s world, audio and video recordings can be made by almost anyone. From smartphones to sophisticated studios and sound stages, large amounts of media content are created daily. And as our world becomes increasingly and audibly congested, the rate of ruined recordings is rising in tandem. Human error, unexpected electrical or mechanical interference, and unwelcome intrusions from aircraft, cell phones, pets, people, and Mother Nature regularly impact even the most seasoned professional. Many times, it just isn’t possible to record that “perfect take” over again, particularly when editing coverage of a live event, or working to meet budgets and deadlines.

Whether you’re a professional or just getting started, you’ve probably run into difficult audio situations like those mentioned above, and wished you could correct what seemed like an impossible dilemma. Using a tool like iZotope RX can help you repair any audio issues or reduce background noise to get better quality audio.

How do I clean up audio?

Cleaning up your audio with iZotope RX combines familiar visual selection tools that are found in plug-ins and digital audio workstations (DAWs) with a visual spectrogram display and advanced audio processing, enabling you to perform powerful audio edits. 

The goal of good audio repair and restoration is to render the best possible sonic result with the least audible human intrusion. In essence, your intervention in the original recording should be transparent and not introduce new artifacts that distract the listener. 

Sometimes it’s possible to solve an audio problem entirely, and other times it’s about finding the right balance between reducing the problem and preserving the original audio. It’s useful to remember that no recording is truly perfect, and any statement as such is purely subjective.

Cleaning up your audio can yield the following results:

• Reduce both ambient and signal-based background noises such as hiss, hum, and buzz—without sacrificing the fidelity and clarity of the original audio.
• Isolate and then reduce or accentuate specific audio events, such as sudden background noises.
• Replace damaged or missing sections of an audio file with seamless, natural sounding patches.
• Eliminate pops, clicks, and mouth noises without audible artifacts.
• Repair audible analog and digital clipping with perfect precision.

Is there a way to remove background noise from audio?

Yes, there are ways to reduce and even remove background noise from audio. Background noise in recordings, if left untreated, is likely to create problems down the road when EQ and compression are applied. Frequency boosts or cuts and dynamic range adjustments can make the noise more noticeable. 

There are two types of background noise: steady (also called ambient noise) and sudden background noise. Steady background noise means noise that is not changing, like hiss, hum, and buzz. Removing steady background noise can improve the overall listening experience, increase intelligibility in dialogue tracks, remove interferences like electrical hum from a musical performance, and make it easier to combine different audio files into one scenario when mixing sound for picture.

Sudden background noise includes coughs, ringing cell phones, beeping, etc. Sudden noises can include a wide range of intrusive sounds that don’t fall into the steady or impulse categories. These can include a cell phone ringing at a violin recital, a door hinge squeaking during an interview, or traffic noise interrupting the dialogue being recorded for a film. 

Most types of interference, especially those that happen on dialogue recordings, can be tackled with iZotope RX plug-ins including De-noise, De-hum, Dialogue Isolate, De-Bleed, Spectral Repair, and more.

What does background noise removal sound like?

Here are audio examples of audio cleanup and background noise removal using Dialogue Isolate in iZotope RX. 

Take note of the differences you’re hearing in the before and after of this interview using RX Dialogue Isolate. Notice how the background noise disappears with minimal disruption to the interview itself?

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Before you begin: learn the key elements of audio cleanup and background noise removal

Before you learn how to remove background noise and clean up audio from your recording, it’s important to get familiar with the tools used to process the audio. 

All of your audio edits will be done by viewing a waveform or a spectrogram. A spectrogramis a detailed view of audio, able to represent time, frequency, and amplitude all on one graph. A spectrogram can visually reveal broadband, electrical, or intermittent noise in audio, and can allow you to easily isolate those audio problems by sight.  

Much of the process in audio cleanup involves removing artifacts. Artifacts are sonic material that is accidental or unwanted, resulting from the editing or manipulation of a sound.

Cleaning up audio typically involves working with the following types of processors:

RX has many modules based on these types of processors to tackle certain audio problems. For example, if your recording has guitar noises such as squeaks, picking sounds, or the hum and buzz that comes from guitar pickups or amplifiers, RX offers Guitar De-noise to help you easily adjust these noises or eliminate them completely. 

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The process of recording, editing, and mixing for mediums such as TV, film, and online videos is often challenging. From news reports to reality TV and streaming, the current emphasis on field recording (made possible by advances in portable recording technology) also introduces audio problems such as distortion and background/ambient noise, to name a few.

Here are some of the most common types of audio issues and ways to clean them up. 

Determine the type of unwanted noise you’re dealing with

Listen to your scene. Is there audible traffic in the background of a scene? Is there an air conditioner fan that’s creating noise in the background? Are you hearing digital clicks and pops from an electronic interface? These different types of audio will require different repair processes and techniques.

Voice Recordings

There’s a lot to watch out for when recording the human voice. Plosives, weird mouth sounds, and background noise are common audio issues in voice recordings. A standard process to clean up voice recordings to sound clear and professional can be the following: 

• Use RX De-plosive to remove plosives
• Use RX Mouth De-click to eliminate unwanted mouth noises
• Use RX Spectral De-noise to reduce or remove background noise

NEW: Speech to Text Navigation and Multiple Speaker Detection

Working on a scene with multiple speakers? The newest version of RX now has Text Navigation as well as Multiple Speaker Detection to help find and tag the sections of speech associated with each individual voice.

Steady Background Noise

Background noise such as cars passing by or audible fans and humming from nearby electronics can distract listeners from the scene and make it harder to hear what’s important. To reduce steady background noise, tools like RX Spectral De-noise or Voice De-noise can be useful to reduce a constant hum or fan noise. 

Our Order of Operations tutorial details all of the steps to clean up a podcast recording that includes a fan noise in the background, among other audio issues. Listen to RX Spectral De-noise and Voice De-noise in action: 

Sudden Background Noise

Sudden or intermittent background noise like alarms, beeps, dogs barking, can take a listener out of the scene completely. Gaps, dropouts, and short sections of corrupted audio are also a common audio problem. These can be caused by everything from a loose audio cable to digital errors. 

These audio problems tend to occur suddenly and last for a short duration—that’s what differentiates them from the conventional noises we dealt with above. 

RX Spectral Repair can help push unwanted audio events into the background, particularly useful if the unwanted audio events don’t completely obscure the desired signal. 

RX Spectral Repair can also replace damaged audio, including dropouts and gaps. It can resynthesize audio using the audio information surrounding the damaged area.

Room Tone

Room tone is the natural noise of your recording environment that’s impacted by the materials of the space and any existing background noise. When room tone suddenly goes missing, the brain notices. It becomes clear that the performance was artificially edited.  

If we add a layer of room tone under audio that was recorded in a separate session, the edit is much more likely to be disguised, which is what we want. RX Ambience Match can help you preserve the room tone of your recording throughout the editing process. 

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Learn more about Audio Cleanup in part 2 of this article.