RX5 by iZotope


Rx5 is an audio fireman – you don’t know that you will need it until you do. It is an industry standard offering the best tools that can be found with just one purpose: to save your audio file.


by A. Arsov, Jan. 2016


RX5 is the most advanced audio repair and restoration audio editor you’re likely to find, able to fix most audio issues, rescuing your badly recorded clips, or even your otherwise perfect take that contains one or two unintended, unpredictable sounds, like noise from outside. It is a “Photoshop” for the audio world. It is also an essential tool for any professional or even semiprofessional video producer.  No matter whether you are just filming small weddings or working on a big budget blockbuster, you will need this. I presume that RX5 also saved many documentary movies, since it is almost impossible to make a perfect audio take in unpredictable conditions. You probably won’t buy this one just to fix a family video (but in most cases it could be cheaper to buy RX5 than sending the video to some pro houses) but if you need it at least once on month then you should definitely consider it. It can remove plosive pops from dialogue (advanced version only), it can also remove clicks or hum or any other sort of noise, it can remove reverb from your recordings, fix bad level issues (advanced version only) and even selectively remove unwanted sounds that appear in your recording, like a telephone ringing in a background of a dialogue or music take without effecting the main sound. It uses some sort of “intelligent replace function” analyzing the signal around the troubled signal. So you can remove a string fret noise from a guitar take or microphone stand rumbles from a vocal take. The advanced version also offers an “ambience match” function that allow you to fill the gaps with the same ambience or even adding ambience from one take to another take, giving the impression that all takes are taken in a same place. If you are in a movie, documentary job, than this one can save you many hours of work.


RX5 is also the right solution for restoring clips from old recordings recorded with lo-fi recorders, or takes taken from vinyl or old tapes. It’s essential for bigger radio stations for fixing any out-of-the-studio recording takes. It could also be useful at the mastering stage, especial if you are working with live recordings.


Main Graphical Interface

On the left we get a menu containing all the modules, the tools that will help you repair and restore your audio file. We will get through the modules a bit later. The rest of the graphical interface is filled with a wave view, where we can zoom any part of the audio file, selecting the tiniest part, not just vertically or horizontally, but even selecting just any separate detail in the audio just as we do with part of a picture in Photoshop. Of course, with the bottom left slider, right under the wave window we can slide between waveform and spectrogram view, setting the opacity of either of those views. The default setting is in the middle, allowing us spot any deviations containing different frequencies or different energy, being presented in spectrogram like a small stain somewhere in the clip, looking almost identical like those X-ray pictures from the movies. We get a whole palette of selection tools; the Time selection tool is the one that we are used to. It selects the region of the waveform from left to right. The next one is the Time + Frequency selection tool, allowing you to select various squares anywhere in a clip – small, big, long or high. The frequency selection tool, as its name suggests, allows you to select just a frequency range, selecting a horizontal segment of a whole file. Lower frequencies are in the middle while higher are closer to the outside edges of the waveform / spectroscope window. The lasso selecting tool is the perfect solution for isolating small parts, ideal for selecting just an intruding sound and replacing it using the Spectral Repair module. The paint selection tool allows us to select bigger parts of the sound clip. The last selection option between all the selections buttons at the bottom of graphical interface is a Harmonic selection tool that allows us to select up to ten subharmonics of a preselected part.

Of course there are also plenty of time meters at the bottom to let you know where exactly you are in a longer file, also displaying the start and end times along with the duration of the selected region. The standalone version also has an option to record directly in the editor’s waveform window. Yes, standalone means that most of the restoring modules are also available as VST plugins. The new version also brings an option to select markers and regions, so big files are no longer a big problem.



Let’s start with Corrective EQ, as this could be a good first step preparing audio for repair and restoration. This is a 6-band precise EQ with low, high and band filters for removing low rumble or harsh high end.

The next ones are the De-Click, De-Hum and De-Noise modules. All modules come with bunch of useful presets and options. De-Click also has a dropdown menu where you can choose if this is a single click, repeatable periodic or regular clicks. De-Hum and De-Noise also have a learn function, so applying editing is just a few clicks away. All you need to do is to set the threshold, sensitivity or reduction level (there are also a few other parameters, for more detailed editing). For better and more precise results we could select an option to listen only to the effected signal. As a bonus, De-Noise even has two different modules built under the basic one. The first is the Spectral De-Noise and the second is the Dialog De-Noise module.

Spectral Replace is one of the most impressive modules allowing you to select any sound or noise that should not be in a clip and simply remove it, and at the same time filling that gap by analyzing the harmonics around problematic areas (yes, we can select more than one part of the clip at once) adding material that is cloned and recalculated from the harmonic characteristic taken from around the problematic area. As harmonics are not just cloned from one spot but being really recalculated from all areas around, the end result is really magical. Of course good results are not so self-evident and require some surgical work, achieved by precise selection and a few additional tweaks. After a little trial and error, thankfully there are not so many sliders inside the Spectral Replace editing window, even the average music enthusiast can become a skilled audio engineer. Before you start your surgical practice I recommended you take some time to study the video clips accessible on the iZotope Youtube channel ( https://www.youtube.com/playlist?list=PL4dISychPQEsxHEurjxnooOEoR5I1D-O9 ).

De-Reverb has a fairly self-explanatory name. Yes, I run into this issue many times. Very helpful when you get some heavily reverbed clips that use quite a different space from the one you intend to use.

Instant Process is an option that we find under the main clip window allowing us to select an action that will be automatically processed as soon as we select part of the clip. So, all you need to do is to select click by click, or a sound that should be replaced, or an area that should be faded. It depends which action is selected in the window near the Instant Process button.

The other very handy thing that can help us process more files at once is Module Chain. It is actually a rack where we can set a few modules with additional settings in a row, being activated by just one click.

There are also a few other Gain and Dither functions along with signal generator, spectral analyzer, resample, third part plug-in support to add your favorite VST plug-ins, and as the last one, Channel Op, an module for phase and delay taming.


Pay More, Get More – Advanced.

All these modules and options are available in the standard version of RX5. The advanced version brings some very advanced (nomen est omen) really usable modules that can be a true life saver for all users that work with sound on a daily bases – production houses, recording studios or radio stations.

The first one is the De-Plosive module that can be applied to the whole file removing plosive pops and microphone bumps from your audio clip, giving far better results than just a low or high pass filter on a file.

Leveler is a module that can analyze the whole clip, achieving the same result as we got in olden times by driving a gain fader in real time. After the effect is processed, you’ll get the volume line with all the volume enhancements along with lots of control points that you can further adjust manually to taste. Of course the module window offers some additional independent controls for breaths and esses, determining the level of the applied De-Esser and determining how much breath will be reduced.

The Loudness module is the one that could help you to set your clip at the level that is required by some institution. Minus six decibels for video production, or indeed any value, according to the standards that some radio stations require. You don’t want to know what some radio or TV stations do when the signal doesn’t match their standard (fixed with macheteTM). I can just recommended you prepare it exactly as they require.


The Ambiance Match module can extract ambiance, intelligently applying it to gaps between the recording takes or even applying it to a new file. When you will need it, you will know. Sometimes when my kids are watching a movie and I’m sitting away from television, I can hear when a voiceover is used instead of using the set location. Big production always takes care of such details, adding appropriate ambiance to the voiceover, achieving a greater level of authenticity.

The EQ Match module can analyze harmonic content from one file and apply it to another. In the past I spent hours trying to match dialogs recorded in different places under different conditions. When you’ll come to this issue, you will be very thankful for this module.

Time and Pitch is similar to the one that we find in many modern DAWs, so I presume there is no need to explain what it does. As a bonus it also has an option to type in source and destination BPM for musical clips. It also offers a few different stretch and pitch algorithms.



There are some tools implemented in iZotope RX5 that maybe we could find in some other plug-ins, but as a whole it is a totally unbeatable tool offering some top-notch repair modules that cannot be found elsewhere. After some trial and error even unskilled users can fix many audio issues. If you have some skills in this area then only the sky is the limit. I have semi-pro video equipment and some additional microphones, but even ideal recording conditions are seldom perfect. So RX5 saved quite a few of my video clips, fixing even the most troublesome ones. Applying compression and reverb to unclean material will only worsen the end result, so after cleaning the audio tracks I could apply all the post production effects without worrying that background noise, clicks or camera hum destroying my take.

If you are in any serious audio production then I presume you already have this one, but anyway, if you are working with a lot with video clips or if you mess around a lot with sound clips then you should definitely consider getting this. There are plenty of audio issues that simply can’t be fixed without iZotope RX5.

For more information, video tutorials and dirty details, visit:


Standard edition will cost you $349 USD / €325 EUR, and the price for Advanced is $1,199 USD / €1,099 EUR.

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