Audio restoration software are tools that in theory, we should never need. After all, we all record audio at the correct level in ideal locations, without any technical defects or any other outside influences. But in this real world we live in, we are presented with a wide range of audio that is recorded too high and so is distorted or recorded too low so that when we boost it is noisy. We end up with location recording with noises that we don't want or spill from adjacent sources. Maybe it was too windy, or the mic was rubbing on the person's clothing. These are just some of the reasons we turn to audio restoration software to help us resolve.

In this article, we highlight a selection of audio restoration software packages, some stand-alone, some plug-ins and some that offer both options that we think you should try out.

You Might Need More Than One

Our experience has also shown that it is sometimes worth having more than one of these in your tool kit because they all work differently and so for one audio example one of these will do a better job than another, and on a different audio example another one will do the best job.

iZotope RX 8

Trusted by the top audio pros around the world, iZotope RX is built on years of extensive research in advanced digital signal processing and machine learning.

RX 6 brought cutting-edge technologies for post-production like lav mic de-rustle, dialogue isolation, and intermittent low-end wind rumble removal. It also introduces creative approaches to age-old music recording problems like microphone bleed, sibilance, mouth clicks, and breaths.

With RX 7, iZotope added Dialogue Contour, to be to change the intonation, a dedicated dialogue De-reverb module, multi-channel support up to 7.1.2, Repair Assistant, which uses AI to analyses the audio and offer options for you to consider and Music Rebalance, which uses source separation, identifying vocals, bass, percussion, and other instruments, enabling you to be able you to change the mix after the event.

iZotope RX 8 added Spectral Recovery, which restores lost frequencies above 4 kHz, turning bandwidth-limited audio into clear, articulate recordings, a dedicated Guitar De-noise module, which although refined for removing hums and buzzes from guitar tracks is also great for any hum and buzzes you might have on any type of audio. RX 8 Advanced also brings a Wow and Flutter module, which corrects pitch variations and fluctuations associated with tape, vinyl and optical transfers.

iZotope RX 8 Pricing

• RX Elements - $129

• RX 8 Standard - $399

• RX 8 Advanced - $1199

Accusonus ERA Range

Accusonus has changed its model from a range of single-function tools available to buy as single tools or as part of a bundle to mainly offering bundles available on subscription. In this article, we are going to look at the ERA Bundle Standard and the ERA Bundle Pro.

• Noise Remover allows you to clean up your audio with one button, everything else is under the hood. It’s as simple as turning it on and off!

• Voice Deepener is designed to make your talent’s voice sound more like they hear it themselves and give you that “movie-trailer” effect with a single dial.

• Mouth De-Clicker highlights all mouth sounds, lip smacks and saliva crackles in your track. You can then remove them quickly with a simple interface.

• Voice AutoEQ is a relatively new plugin, which listens to the dialogue track and allows you to enhance it in real-time. Use it to improve voice clarity in a way that’s impossible with normal EQs.

• ERA Voice Leveler is designed to easily fix distracting volume differences. Smooth out uneven audio levels, such as those caused by actor or microphone movements.

• Reverb Remover can remove all that ‘empty space, such as those captured during a wedding ceremony inside the church and make your recordings sound tighter and focused.

• De-Esser is able to smooth out those annoying ‘s’ sounds and make your tracks easier to listen to. Watch the software automatically detect the S’s in your waveform and fix the problem.

• De-Clipper repairs distorted & over-saturated audio that would otherwise be unusable. Either you work with dialogue or with other audio tracks, you might often get stuck with “clipped” audio.

• Plosive Remover suppresses “spitting” b,p & t sounds and instantly improve your dialogue recordings. Sometimes it’s simply not possible to use a pop shield. That’s when distracting p-pops ruin your dialogue.

• Audio Clean-Up Assistant avoids juggling between multiple plugin windows and parameters. ERA Audio Clean-Up Assistant allows you to work smarter and faster. It combines several ERA Standard plugins and offers carefully-curated presets that you can use as a starting point for your audio processing. Build your own audio repair chain - which you can recall anytime - or save time by choosing from the CleanUp Assistant’s presets, rather than configuring them yourself from scratch.

In the ERA Bundle Pro you get all the above tools as well as the following tools…

• Noise Remover Pro is an intuitive tool for professionals, which in most cases, all you need to do is tweak the large white dial! If that isn’t enough, Noise Remover Pro also offers sophisticated multi-band processing. Curated presets are also available, so you can speed up your workflow even more!

• Reverb Remover Pro has a unique tuning and UX design where the large central knob will help you get the job done in seconds, or you can dive in and fine-tune the settings for surgical precision if time permits. See and hear what’s being removed using the DIFF button.

• De-Esser Pro is based on multi-patented Accusonus algorithms. It simply works and allows for efficient sibilance reduction from audio recordings. You can watch the software automatically detecting the S’s in your waveform and then fix the problem by turning the dial!

• ERA Room Tone Match is only available as an AudioSuite AAX plug-in for use with Pro Tools. It identifies the background ambience under speech and helps you seamlessly stitch and even out different ambience beds.Extract and smooth the room tone and maintain the natural feel of your scene, without resorting to tedious workarounds!

Accusonus ERA Bundle Pricing - Subscription Only

• ERA Bundle Standard - $7.99 per month

• ERA Bundle Pro - $24.99 per month

Sonnox Restore Bundle

Sonnox Restore is a suite of three plug-ins designed for audio restoration. Its advanced algorithms and novel features are designed to allow fast and extremely effective removal of pops, clicks, crackles, scratches, hum, buzzes and background noise from virtually any recording without damaging the important 'wanted' audio content.

With their interfaces, Sonnox Restore's plug-ins are designed to be quick and easy to use. The DeClicker has a dialogue mode and 'exclude box' for retaining wanted audio; the DeBuzzer has 3 frequency ranges and real-time tracking for wandering problem frequencies and the DeNoiser with its independent de-hisser offers powerful real-time broadband noise reduction.

• Oxford DeNoiser - The DeNoiser Plug-In with its integrated de-hisser delivers broadband noise reduction in real-time. The process is based on a continual analysis of the input signal in order to build a noise profile. Alternatively, you can use Freeze Mode to sample a section of audio containing just target noise. Sonnox acknowledges the delicate balance between removing noise and retaining the character of your original recording, so have added a Warmth control to return some richness and added a DIFF function to audition only the removed noise.

• Oxford DeBuzzer - This has been created for fast and effective removal of buzz, hum, whine and whistles. You use the intuitive display to help isolate the fundamental frequency – it constantly gives feedback on the top contenders – or you can define it manually with the help of a tone generator. If the fundamental wanders, the default Auto Tracking Mode is designed to follow it in real-time. The harmonics of your problem fundamental frequency will also be tracked. All that remains is to engage the default comb filter or the optional parametric EQ, and then fine-tune the content that’s removed using DIFF auditioning.

• Oxford DeClicker - Declicker has been designed to remove pops, clicks and crackles using three discrete sections. Each has a threshold and sensitivity control to define the number of events that are detected and removed. The unique Events Graph shows the level and duration of each pop, click and crackle as it’s detected in three separate colour-coded groups.  Sometimes there will be events detected that represent audio you want to keep rather than remove. So Sonnox has built the Exclude Box to refine the number of repaired events, and also Dialogue Mode for independent control over speech in the programme.

To learn more about Sonnox Restore check out our article Sonnox Restore Now AAX 64 Bit Compatible & With A New Price Too.

Sonnox Restore Compatibility And Pricing

You can buy the plugins separately or buy the bundle and save 25%…

• Oxford DeNoiser - $250.03

• Oxford DeBuzzer - $250.03

• Oxford DeClicker - $250.03

• Sonnox Restore Bundle - $561.27

Acon Digital Restoration Suite

Restoration Suite 2 from Acon Digital is a suite of four plug-ins for audio restoration and noise reduction:

• DeNoise 2 is a plug-in designed to reduce noise such as hiss, wind noise, buzz and camera noise. The noise can be reduced automatically in the adaptive mode or after measuring the characteristics of the noise in the noise profile mode. New in version 2 are dynamic noise profiles that capture the dynamic properties of the noise so that noise that fluctuates over time, such as wind noise, can be more effectively reduced. The algorithm has also been improved and is now even less prone to typical de-noising artifacts.

• DeHum 2 targets hum and buzz typically introduced by poorly grounded electrical equipment, but also other tonal noise sources like electrical motor noise. The hum detection algorithm has been improved in version 2 and there’s now a new Scan button that automatically fine-tunes the fundamental hum frequency.

• DeClick 2 is designed to remove impulsive noise such as clicks, crackles and thumps. These distortions are frequently encountered on LP and 78 RPM records, but also occur in digital recordings due to drop-outs or distorted data packets. DeClick 2’s thump reduction works also effectively on vocal recordings with unwanted plosives. The algorithm has been improved in version 2 and is now less prone to reducing attacks and transients in the wanted signal.

• DeClip 2 restores audio recordings distorted by analog or digital clipping with an improved algorithm.

All four plug-ins have received major improvements both in the processing algorithms and the user interface compared to version 1. 

• DeNoise 2 introduced the novel dynamic noise profiles that help reducing noise that varies randomly over time, such as wind noise or rustle from lavalier microphones.

• DeNoise 2, DeClick 2 and DeHum 2 now support Mid/Side (M/S) processing, which can reduce unwanted fluctuations in the stereo image.

• The core algorithm in DeClick 2 received major improvements and now better preserves transients and can be pushed to higher click and crackle sensitivities without introducing artifacts.

• DeHum 2 has a new automatic fine-tune button that triggers automatic estimation of the hum noise frequency. The hum tracking and suppression have also been improved. 

• DeClip 2 was improved in terms of audio quality and now offers an improved reconstruction of clipped signal peaks.

All the plug-ins in the suite now support surround and immersive audio formats up to 7.1.6 channels

Acon Digital Extract:Dialogue

Extract:Dialogue is a plug-in that is designed separate dialogue from common types of background noise such as wind, rustle, traffic, hum, clicks and pops. The algorithm works in real-time and is based on machine learning. Acon Digital has trained it on thousands of high-quality voice recordings as well as an extensive set of common noise sources to enable the artificial intelligence to automatically distinguish dialogue from noise without user interaction. The aim of all this AI is to make Extract:Dialogue extremely easy to use – just add it to your dialogue bus and let it do its magic.

Even though the noise reduction is fully automatic, the plug-in interface does offer simple controls to adjust the sensitivity of the noise detection and the maximum noise attenuation. The sensitivity can even be adjusted independently in up to three frequency bands. The maximum attenuation control is very handy when you only want to reduce the noise without removing it completely. All the parameters are fully automatable as you would expect.

Acon Digital Pricing

• Restoration Suite 2 - £79.90

• Extract:Dialogue - £79.90

TODD-AO Absentia DX 3

The underlying aim of this plugin is analysing production dialog recordings and then removing obvious hums, wireless rings, and ticks, while maintaining the integrity of the human voice remains the same. However, the latest iteration of Absentia DX sees a change to a subscription model and an extension to the features. It’s no longer a one-trick pony.

Standalone Or Plugin - You Choose

The new V3 plug-in includes all the tools from the Standalone app and a local library that makes processing 3x faster. The Hotkeys shortcuts will speed up editing. You can use the Standalone Application to Batch Process the complete Sound dailies folder or use the Pro Tools plug-in when editing or mixing to make deeper processing to some clips.

Absentia DX contains 5 different tools…

Broadband Reducer is now able to process deeper than before with a lower noise peak model.

Hum Remover automatically removes hum from recordings. The Hum Remover Smooth setting is designed to be safe for all dialog.

Air Tone Generator enables you to replace dialogue with room-tone while maintaining production moves.

Doppler enables you to remove hum or whistles that vary in pitch.

Phase Synchronizer enables you to cut Boom and Lavalier together, and avoid phase cancellation issues.

Sonogram Player enables you to view the Spectrum of a poly-wav file and play it channel by channel.

Absentia DX Pricing

There are two options, both subscription models…

• Server is for users that don't need to carry the license with them regularly. The license is activated on your machine, but you can request to move it. Absentia DX Server cost $120 for the first year and then $40 for subsequent years as long as you renew it before the license expires.

• iLok is for users who work on different facilities and need to carry the license around and so the license is activated on a 2nd Generation Pace iLok2 or later. Absentia DX iLok cost $150 for the first year and then $50 for subsequent years as long as you renew it before the license expires.

Klevgrand Brusfri

Brusfri actually means ‘noise free’ in Swedish, which perhaps gives an indication of what it can do. It is an audio noise reducer, with a simple and straightforward interface. It is well suited for cleaning up noisy audio recordings while retaining sound quality. Unlike some other noise reducers on the market, Brusfri doesn’t mess with audio phasing to suppress noise (a technique that often comes with audible side effects). Instead, multiple fine-tuned gates are used to handle the unwanted noise.

• Several frequency-trimmed expanders build an intelligent noise suppressor

• No phase-altering, which leaves the desired sound untouched (no squishy artifacts as in many other noise reducers)

• Intuitive and unique user interface

To learn more about Brusfri from Klevgrand check out our free tutorial on how to use Brusfri and see if Brusfri From Klevgrand Is A Challenge To iZotope RX? Check Out This Video

Klevgrand Brusfri Pricing

• Brusfri is priced at $59.99

Accentize Speech Restoration Bundle

The Accentize Speech Restoration Bundle is made up of VoiceGate and DeRoom Pro.

• VoiceGate is a Machine-Learning based audio plug-in, which can be used to reduce noise from speech and vocal recordings in real-time. An artificial neural network has been trained on more than 100 hours of audio data to learn the characteristics of human speech. The plugin can automatically adapt to a variety of different noise types and lets you easily control the amount of noise reduction you need.

• DeRoom Pro is a Machine-Learning based reverb removal audio plug-in built for professional use. An artificial neural network has been trained on many different room scenarios in order to be able to separate direct sound from reflection components. The real-time processing scheme provides instantaneous feedback while changing parameters and allows seamless integration into your workflow without having to switch applications.

To learn more about both VoiceGate and DeRoom Pro from Accentize check out our article Accentize DeRoom Pro And VoiceGate Tested - Find Out What We Think Of This New Audio Restoration Bundle.

Accentize Speech Restoration Bundle Pricing

• VoiceGate - €129

• DeRoom Pro - €199

• Speech Restoration Bundle - €245

CEDAR Studio 9

When it comes to noise reduction, for many, CEDAR is at the top of the food chain. If you work with dialogue, there is a good chance you have used, or are at least familiar with, CEDAR Studio 9. This bundle is made up of eleven processes all designed to enable you to eliminate a wide range of common problems and significantly improve the sound quality of your audio. Each CEDAR Studio process has been derived from their multi-award-winning CEDAR Cambridge flagship product and aims to provide unsurpassed results, quickly, and with the minimum of fuss and user intervention.

CEDAR Studio DNS includes both DNS One and DNS Two, for all of your dialogue noise suppression requirements in post-production and elsewhere.

If you work with film dialogue, the speed, flexibility, and ease of use of DNS One provides solutions to audio problems that you could not previously solve. It's a standard for multi-channel post-production in the film, video, and TV industries. It's designed for removing motor noise from recordings, eliminating electrical interference, and helping to clean up recordings suffering from unfavourable acoustics and poor microphone locations.

In almost all cases, using DNS Two is as simple as switching on LEARN and then adjusting the attenuation to obtain the desired amount of noise reduction.

CEDAR Studio Restore comprises no fewer than eight advanced audio restoration algorithms…

Declick offers an improved impulsive noise detection and a better interpolator, designed to offer superior performance across a wider range of materials than ever before.

Decrackle boasts an ability to dig into the damaged signal to identify and remove all manner of ground-in and grungy crackle without damaging the wanted audio. It also removes many forms of buzz and some amplitude distortions from material ranging from cylinder recordings to current broadcasts contaminated with lighting buzz.

Manual Declick is for restoring the extended scratches and clicks encountered on many audio media - film, tape or disk, whether analogue or digital. Its dual algorithms, optimised for long clicks and scratches, will remove noises such as those found on optical soundtracks, as well as drop-outs and extended digital errors.

Dethump has been created to eliminate the extended low-frequency thumps that cannot be restored using conventional declicking processes and filters. It replaces the unwanted sound with restored low-frequency audio and is the ideal tool for removing many of the previously intractable problems associated with optical soundtracks, cylinders, 78rpm discs, and even modern recordings when, for example, microphones and stands are bumped.

Auto Dehiss has an advanced algorithm that has been designed to be far less susceptible to the unwanted side-effects sometimes called twittering, glugging, the 'underwater sound', and even 'space monkeys'. A manual mode is also offered for fine-tuning the results when wanted.

Debuzz has been designed to quickly remove all manner of buzzes and hums with fundamentals as high as 500Hz. It will track wandering tones and, unlike traditional filters, can successfully restore the audio without unwanted side-effects such as limited bandwidth or the hollow sound introduced by comb filters.

Declip 2 removes clipped samples and reconstructs the original signal, improving clarity, eliminating distortion, and restoring the original dynamic range of the damaged audio.

Adaptive Limiter employs another algorithm developed by CEDAR that constrains the peak level of the output while retaining the integrity of the input and with its advanced resampling and noise shaping capabilities, is ideal for mixing, final mastering and other creative duties.

CEDAR Studio Retouch, first seen in 2002, is arguably the product that changed the audio industry and could be the most effective way to deal with otherwise intractable audio problems.

Nowadays, it allows you to mark and process complex areas in its spectrogram using the types of tools commonly found in powerful photographic and image manipulation software.

This makes it possible to identify all manner of sounds and noises which can then be manipulated using any of the processing tools at your disposal.

Retouch lives within a plugin window inside your DAW of choice. It takes a little adjusting to get used to the interface and workflow, but once you do, not having to roundtrip every clip really does speed up the process on a day of heavy spectral repair work.

CEDAR Studio 9 Complete Pricing

• You can get CEDAR Studio 9 Complete for $4,999

Descript Studio Sound - Honourable Mention

Descript is the company behind some smart audio transcription software, or should we say very smart. In a very short space of time they’ve created a platform that can record video, screen capture, audio, transcribe it and do lots of clever stuff, often with just the click of the button.

What Descript are aiming to do is help podcasters, video tutors and a whole host of other people who record video and audio make the best possible content.

Both Russ and Mike have tried Studio Sound from Descript and we have to say it is pretty amazing. Given the quality of the original recordings using domestic recording devices in less-than-ideal environments, we have to say we’re impressed by what Studio Sound can do.

It’s not ready for professional use, mainly because to use it you have to use the Descript software, which would make the workflow in a professional studio not very practical because everything has to be loaded up to the cloud and all the AI is also in the cloud.

It would also be nice to have some adjustment as at times it sounds overcooked. However, given that this is the beta version and their first attempt at trying to fix bad audio, imagine what Descript could do with this technology if they delivered it in a way that could fit into a pro workflow.

We have already started mixing a little of the unprocessed sound in with the processed version to help with the slight ‘overcooking’ Also some use of EQ on the low end can help make the processed version more natural.

However, given the target audience is going to be casual or semi-pro users, this thing is brilliant. A lot of pro audio companies should take note of the simple workflow that professional users could benefit from, all the examples shown here were done with a tick box. That’s as hard as it gets!

To learn more about Studio Sound from Descript check out our article Impressive Software Takes Aim At iZotope RX - Descript Studio Sound Tested

Descript Studio Sound Pricing

Studio Sound currently comes free with Descript and you can even start with a free Descript account which offers a time-limited amount of transcription time per month.

What Do You Use?

These are have it, a selection of very powerful audio restoration products that all do a great job. Which ones do you use? Let us know in the comments below...