INTRODUCTION
This overview article will take an in-depth look into the iZotope RX5 Advanced Audio Editor software. I will go through all the major repair and audio enhancement modules and give you a short introduction on what you can do with them.
CONTENT
iZotope RX5 Audio Editor comes in two versions (RX5 and RX5 Advanced) and the difference between these versions is noticeable. The RX5 has all the basic repair functions and even some audio enhancement features in it that will definitely help the average user to get rid of nasty audio problems. RX5 Advanced is geared more towards professional users and comes with advanced versions of the repair functions, a wide array of different audio enhancement features and you also get the Insight metering suite, bundled as an additional plug-in.
iZotope has provided a more detailed list of the differences between the RX5 and RX5 Advanced on their site and you can check it out HERE.
Main interface
The main bulk of the interface is reserved for displaying the audio with waveform and spectrogram modes. Below you have a quick access to all the basic functions, meters and settings so you don’t need to browse through a bunch of menus to get access to a function you want. On the right you can open the modules and tweak their settings to your liking. On the bottom right corner you have an undo window where you can easily undo processes you have done and also do quick before / after previews of your audio.
De-clip
De-clip repairs digital and analog clipping artifacts that result when A/D converters are pushed too hard or magnetic tape is over-saturated. As with all of the modules you get a set of presets that you can use as good starting points. On the left you can manually adjust both positive and negative thresholds or you can use the suggest button that automatically sets the thresholds to optimal settings. On the right you can choose between different processing quality settings but I tend to leave it at high. Then you got a makeup gain slider that applies gain to the selection after declipping. Sometimes after processing the file you can see that the audio file is still clipping and you can attenuate it with this slider. Below the makeup gain you have a post-limiter option which when selected keeps the waveform under 0 dB. On the bottom you have the usual preview, bypass, compare and process buttons.
De-click
De-click is meant to eliminate clicks, crackles, pops and digital impulse noises. There are three main tabs in the de-click module. De-click automatically finds and repairs clicks, de-crackle removes less prominent or continuously happening clicks and interpolate is good for fixing single clicks or filling large gaps in the audio files.
In the de-click tab you can choose between a single-band, a periodic multi-band and a random multi-band algorithms. On the right you can choose the type of click you want to remove. In the middle you have a sensitivity slider that lets you control the amount of repaired clicks by adjusting the sensitivity of the click detector. Then you have the frequency skew slider where you can choose to detect more clicks at low frequencies or high frequencies. The click widening slider repairs the signal around the click by widening the repair area. On the bottom you have the clicks only option which lets you hear the clicks that you are trying to remove and make sure that you are not overdoing it.
In the de-crackle tab you can choose between different processing quality settings and use the amplitude skew slider to increase decrackler strength at low-level or high-level signals. Then you have the strength slider which determines the overall strength of the decrackler and on the bottom you have the crackle only option which works similarly as the click only option.
There is only one setting in the interpolate tab and that is the quality slider which lets you to control the interpolation order of the samples.
De-hum
De-hum automatically identifies the base frequency of unwanted hum, and removes it from the recording along with harmonics. De-hum has two modes that you can activate, manual and adaptive. Manual mode lets you manually adjust the hum profile or learn it from a selection. Adaptive mode adapts to the changing frequencies so you can use it to track down the fundamental frequency.
On the top you can change the base frequency between 50Hz, 60Hz or Free which lets you adjust the hum frequency either by using the learn button or using the notch frequency slider. Filter Q slider controls the sharpness of notch filters for hum rejection. Then you have high-pass and low-pass filters that you can use to reduce low frequency rumble or high-frequency hiss.
In the middle you have a graphical display of the notch filters where you can adjust the base frequency and on the right you a slope slider that changes the notch depth depending on the order of the harmonics.
On the bottom you have the number of harmonics slider where you can change the amount of harmonics to your liking. Then you have the link harmonics option where you can choose to link them all together, odd/even or none which lets you adjust the harmonics individually. Below that you have checkboxes for Filter DC offset and output hum only options.
De-noise
De-noise is the go-to module when you want to reduce unwanted background noise quickly and easily. Like the de-hum module de-noise has manual and adaptive modes that you can activate. In manual mode you can learn the noise profile by adjusting the individual controls or you can use the learn button to get a noise profile from a selection. In adaptive mode you get the learning time slider where you can control the length of time the denoiser uses to adapt to changing noise profiles.
On the bottom you can choose between different noise reduction algorithms ranging from quality A to D. Quality A is the fastest algorithm and uses the least of CPU resources and quality D is the slowest algorithm but uses a lot more CPU resources so you need a fast computer for that.
Then you got the artifact control slider where you can change the amount of smoothing to reduce musical noise artifacts. On the right you have sliders for threshold and reduction and below both of the sliders you have a chain symbol that lets you unlink noisy and tonal threshold for both of the sliders. Basically this means that if you have an audio file that has tonal elements in it and you only want to reduce the noise and leave the tonal elements as they are then you can unlink the noisy and tonal thresholds for the reduction slider and move the tonal threshold slider down to zero.
If you really want to go under the hood and microtune then you can go to Advanced settings where you can control algorithm behaviour, noise floor and dynamics.
In the dialogue tab you get the usual manual and automatic modes and the learn button which can be used only with the manual mode. Then you have the graphical display where you can manually adjust the noise floor with the nodes. On the right you have a slider for offsetting the noise threshold curve and a slider for changing the strength of the reduction. The cool thing about the dialogue denoiser module is that has no latency so you can use it as a plug-in inside your DAW and it won’t mess up with your sync.
De-plosive
De-plosive module helps you to remove plosive pops and microphone bumps that can occur during a recording. In the module you have a sensitivity slider that helps to adjust the amount of detected plosives. Then you have the strength slider where you can change the attenuation depth of the plosives and frequency limit slider that lets you set the highest frequency to attenuate.
Spectral Repair
Spectral Repair module lets you visually isolate and paint away to remove any unwanted sounds. It is basically like Photoshop but for audio. Spectral Repair comes with attenuate, replace, pattern and partials+noise modes. Attenuate mode attenuates the selection to match the surrounding audio, replace discards the selection and interpolates (fills) it from surrounding audio, pattern replaces the selection with similar audio content found elsewhere in the audio file and partials+noise finds harmonics and noise either side of the selection filling it using interpolation.
In the attenuate tab you can adjust the amount of frequency bands, the strength of the attenuation, surrounding region length, direction of interpolation and even change the before/after weighting of the surrounding audio. You also have a multi-resolution mode that can more efficiently separate unwanted noise and desired audio.
The replace tab has the same adjustment functions as the attenuate tab except the direction function. Same thing in the pattern tab except there is a pattern search range slider which lets you set the time range used to search for audio which matches the surrounding interval.
In the partials+noise tab you have a harmonic sensitivity slider and a checkbox for testing harmonic sensitivity.
Deconstruct
Deconstruct module analyzes your audio and separates the signal into its tonal and noisy audio components. You have individual sliders for tonal and noisy gain and a tonal/noisy balance slider that helps you to adjust the tones and noises in the separation algorithm.
De-reverb
De-reverb helps you to reduce some of the reverb from a recorded space in order to make the dialogue or other audio content useable. On the top you have the usual learn button which you can use to learn the reverb profile of the audio and then it automatically adjusts the reverb parameters.
In the middle you have a reduction slider which controls the overall strength of the processing. Next to that you have dry/wet sliders for low, low-mid, high-mid and high frequency bands and also a slider to adjust the tail length.
On the bottom you get the same artifact smoothing slider that you have in the de-noise module. Next to it you have checkboxes for enhancing the dry signal and outputting reverb only functions.
Leveler
Leveler adjusts the volume of your dialogue to a threshold of your choosing while also controlling the breath and sibilance. You can optimize the leveler either to dialogue or music. You also have sliders for adjusting the target RMS level, responsiveness, dynamic preservation, ess reduction and breath control.
EQ Match
EQ Match enables you to create a consistent sonic sound between two different dialogue recordings. You can learn the frequency spectrum of the selected audio with the learn button. Then you have the slider below where you can set how closely the selected frequency spectrum will be matched to the learned one. Basically you can take two different dialogue files and learn the frequency spectrum of the first one and then apply the learned frequency spectrum to the second dialogue file. In the end you should get two dialogue files that sound pretty much identical.
Ambience Match
Ambience Match modules main use is to fill in consistent ambience beds to seamlessly match ADR to production dialogue. You can learn the selected audio’s ambience with the learn button and then you can use the trim slider to either cut or boost the amount of ambience that will be added.
Time & Pitch
Time & Pitch module comes with stretch & shift and pitch contour functions. In the stretch & shift tab you can use the stretch ratio slider to stretch audio without changing the pitch and with the pitch shift slider you can change the pitch without affecting the length of the audio file. You can choose between three different algorithms: radius, solo instrument and radius RT. Solo instrument algorithm works best when used for monophonic audio content. If you have other than monophonic content then you should use Radius (best quality) algorithm.
In the pitch contour tab you can adjust both time and pitch. You can add nodes to the graphical display and do things like gradually slowing down the audio or just go crazy and wobble it around for experimental purposes. Then below you have a slider that controls the amount of smoothing applied to the pitch contour curve. Finally you have a reset button if you want to start from scratch.
Loudness
The Loudness module quickly makes any mix compliant with network standards across the world, so you can export and deliver your mix to multiple networks. On the top you can choose the loudness standard you are going for and then you can tweak the true peak and integrated loudness values from the sliders on the right if you need to. On the left you have value meters for true peak, loudness range and also values for integrated, momentary and short term loudness.
Corrective EQ
With Corrective EQ you can surgically reduce and remove problematic frequencies. You have all the basic EQ features like high-pass filter, 6 individual bands, low-pass filter, low shelf, bell, high shelf, frequency, gain and Q functions.
RX Connect & Monitor
RX Connect plug-in allows you to send a clip, or multiple clips, to the RX standalone application for editing and repair. RX Monitor enables you to monitor your audio from the RX Audio Editor application through your host application.
Module Chain
Module chain enables you to chain different RX modules together and process your audio content quickly with just a couple of mouse clicks. Starting from left you have a button that lets you to change the order of the modules, turn the module on or off, open the module window so you can tweak its settings, select the modules you want to use, delete a module from the chain and finally add a new module to the chain.
Instant Process Tool
Instant Process Tool lets you simply paint an audio problem away without needing to open a module, choose settings, and then click Process. You just need to click the Instant Process button and then choose the processing method from the pull down menu on the right. You can choose between attenuate, de-click, fade, gain and replace functions. When you have chosen your processing method then you can for example select the brush tool and start painting away the problematic audio content.
CONCLUSION
As you can see the RX5 Advanced Audio Editor has a lot to offer for audio restoration and enhancement purposes. I have just barely scratched the surface of the software so I recommend you to try it out yourself. iZotope offers a 10 day trial period so you will have plenty of time to dig deeper yourself.