How to Remove Background Noise from Audio

Background noise can be a major issue when recording audio, especially if you're not in an ideal recording environment. Whether you're dealing with hum, clicks, or other unwanted sounds, these distractions can compromise the quality of your work, becoming more pronounced during mixing and mastering. It’s at this stage that “fixing it in post” becomes essential—a key part of the audio editing process.

Pro Tools, with its seamless integration of iZotope RX via ARA2, provides a powerful solution for removing background noise. The RX Spectral Editor, included with Pro Tools Artist, Studio, and Ultimate, enables you to eliminate unwanted sounds directly within your Pro Tools workflow. This guide will walk you through the process, helping you achieve clean, professional-quality audio without needing to open separate plugins or applications. Let’s get started!

1. Select the audio clip

Start by selecting the audio clip you want to edit and right-click to bring up the drop-down menu. Select the RX Spectral Editor option. The clip will be analyzed and opened in the tabbed RX Editor window. If you prefer to work with the spectral editor in a separate resizable window, click the detach icon in the tab name.

2. Identify the problematic frequencies

With the RX Spectral Editor open, you'll see a visual representation of your audio in the spectral display. This display shows time on the horizontal axis and frequency on the vertical axis, with the intensity of the frequencies indicated by color or brightness. Brighter and more vibrant colors, such as red, indicate louder or more prominent frequencies, while darker colors represent quieter parts of the audio.

To identify the problem area, look for any anomalies or unwanted sounds that stand out from the main audio content. These will often appear as brighter red or orange portions that aren't consistent with the surrounding audio. For example, a screeching noise might show up as a bright red line or blob that differs from the rest of the spectrum.

Choose one of the selection tools on the top bar of the screen to isolate the noise:

Hold down shift to make multiple selections with any of these tools. By carefully selecting the unwanted noise, you can then proceed to apply the appropriate repair options to remove or reduce the background noise effectively.

3. Choose a repair option

Once the selection is made, there are two main repair options available in the RX Spectral Editor: Attenuate and Replace. With your repair option selected, you can click Process in the bottom right of the spectral editor to apply the changes. Each repair option serves a different purpose and can be chosen based on the nature of the noise and the surrounding audio content. Let’s explore the options and how to choose between them:

Attenuate

Attenuate mode is designed to blend the selected noise into the background by comparing the content inside the selection with the content outside the selection. It effectively reduces the level of the unwanted sound so that it becomes less noticeable and merges seamlessly with the surrounding audio.

Attenuate is particularly useful for reducing constant background noises like hums, air conditioning, or distant traffic sounds, bringing them down to a level where they blend into the background without being distracting.

Replace

Replace mode works by substituting the selected noise with the surrounding material, effectively removing the unwanted sound and filling in the gap with similar audio content.

Replace mode is ideal for eliminating short, discrete noises such as clicks, pops, door slams, or any other sudden intrusive sounds. It ensures that the unwanted noise is entirely removed and replaced with audio that matches the surrounding environment.

Choosing Between Attenuate and Replace

Depending on the specific context of the noise and the desired outcome, one mode might be more suitable than the other. For constant background noises, attenuate often provides a more natural result by blending the noise into the background. For sudden, distinct noises, replace is more effective as it removes the noise entirely and fills the gap with similar audio.

Common Controls for Attenuate and Replace

Both Attenuate and Replace modes share the same set of controls to fine-tune the repair process:

• Process Strength: Adjust the strength slider to control the degree of processing. Increasing the strength will reduce or replace the noise more aggressively.
• Region Size: Use the region slider to change the size of the surrounding area that the editor considers for blending or replacing the noise. A larger region might yield more natural results.
• Weighting Control: The weighting control allows you to give more importance to the audio either before or after the selection. Moving the slider to the left prioritizes audio before the selection, while moving it to the right prioritizes audio after the selection.
• Direction Selection: Decide if the editor should consider the horizontal, vertical, or all directions for the attenuation or replacement process.

Additional Noise Reduction Tools in RX Spectral Editor

• De-click: Remove a variety of short impulse noises such as clicks caused by digital errors, mouth noises, and interference from cell phones.
• De-hum: Remove any amount of hum, ring, or interference without any artifacts or affecting the audio quality.
• Gain Mode: This tool allows you to adjust the volume of the selected area, either increasing or decreasing its level. Unlike Attenuate, Gain Mode does not blend the noise into the background but simply modifies the volume of the selected frequencies. This can be useful for making specific sounds more prominent or for reducing their level within a mix, but it doesn't perform any intelligent blending or noise reduction.

4. Render your repaired audio

Rendering the ARA plugin is an important step to save on CPU resources or to perform additional ARA or elastic audio processing. Rendering finalizes the changes made with the RX Spectral Editor and integrates them into the audio track, freeing up processing power for other tasks. Here’s how to do it:

1. Select the Processed Clips: Highlight the clips that have been processed with the RX Spectral Editor.
2. Right-Click and Choose Render: Right-click on the selected clips and choose the render option from the ARA submenu.
3. Render the Selection: This will render the selection as new clips, effectively applying the noise reduction permanently while keeping the ARA plugin active on your track for further adjustments if needed.

Rendering the corrected audio to a new audio file ensures that all edits are preserved and the processed audio is ready for further mixing, mastering, or other production stages. It also helps to maintain a smooth and efficient workflow by reducing the real-time processing load on your system.

Removing background noise is crucial for ensuring the quality of your audio recordings. By leveraging the powerful tools available in Pro Tools, including the RX Spectral Editor integrated via ARA2, you can efficiently eliminate unwanted sounds and achieve professional-quality results.

Pro Tools offers a complete set of audio editing tools that cater to the needs of music producers, film editors, and podcasters alike. With its industry-standard capabilities, you can polish your audio to perfection, no matter the project. Ready to take your audio editing to the next level? Try Pro Tools today and experience the difference in your productions.

Visit the iZotope website for special offers for Avid customers, including additional free plugins for download.