iZotope's RX is one of the most powerful audio repair tools in the business. So what could a new version add? Quite a lot, as Joe Albano found out...
RX 6 Standard is a comprehensive audio repair and noise reduction toolkit that includes everything from RX Elements and more. Visually identify and repair problems with the standalone RX Audio Editor application, or use the plug-ins in real time in your favorite DAW or NLE. Apr 06, 2010 Why would you want to install an iPad into your car dashboard? Maybe you're radio's LED is way too small, maybe you want to be the envy of all your friends and loved ones, maybe you just want to enjoy some multitouch entertainment on the go? Whatever your reason, this video is for you! Doug Bernards (aka The Sound Man) goes through every step in order to turn a regular dashboard LED.
iZotope’s RX has established itself as the premiere audio repair software - its collection of cutting-edge tools and spectral processing capabilities has been used to clean up and improve countless bits of problem audio over the years. The latest version, RX6, adds a number of significant new features and processors to the party so let’s take a look at what’s on hand in this update..
The RX6 Family
First off, RX6 is now available in four versions.. The top-of-the-line is RX6 Advanced, which contains all the processing modules available for RX, including the new ones, for the most full-featured set of tools. RX6 Standard offers a slightly smaller subset of the full toolbox for a reduced price, but it does contain most of the key modules, including the ones RX is best known for like Spectral Repair. For those on an even more modest budget, RX6 Elements is a smaller collection of basic repair tools, perfect for quickly cleaning up the most common flaws in typical recordings. A full comparison chart is available on the iZotope website. In addition to these options, for post production pros, RX6 Advanced is also available as part of the RX Post Production Suite 2, which also includes Neutron Advanced, Loudness Control and Insight.
General Features
RX6 (I’ll be describing RX6 Advanced here), just like previous versions of RX, consists of a standalone application with a collection of processing “modules”, each of which offers a targeted solution to a specific audio issue. Many of these are also available as plug-ins in all the standard formats (AAX, AU, VST), for use in realtime within your DAW of choice. When processing needs to be in the standalone (some of the more advanced types of audio tweakery, including the graphic techniques of Spectral Repair), RX6 provides a way to quickly transfer audio back and forth between the DAW and RX6 standalone - this varies in different DAWs, from using the RX Connect plug-in to assigning RX6 as the designated external audio editor.
Within the standalone, there are numerous features for enhancing workflow. Module Chains (savable as presets, as are all module settings) let the user assemble and quickly apply a string of modules, speeding up tasks that involve multiple processing. RX6 offers additional workflow improvements: an improved Find All Similar helps to quickly locate similar problems in a longer audio file, and there are new options for displaying the extensive module list by user category.
RX6 also introduces Composite View, a quick way to simultaneously process multiple files. While RX has always had batch processing capabilities via a dedicated window, Composite View is a more efficient way to temporarily group all open files together and apply processing to them all at once. While there are a few common sense restrictions, it could speed up workflow for many tasks that need to be performed across multiple bits of audio.
New Modules
Naturally, RX6 includes all the modules from previous versions, including (among others) De-click, De-clip, De-hum, De-plosive, De-reverb, Spectral and Voice De-noise, Deconstruct, and of course Spectral Repair as well as its collection of utility modules like Leveler, Loudness, Time & Pitch, Resample, EQ Match and many additional general-purpose modules. Some of these have incremental improvements - De-click, De-plosive, Voice De-noise, Ambience Match, Deconstruct and Center Extract all benefit from tweaks to their engines (I particularly noticed the difference in De-click).
To this already comprehensive collection of audio tools RX6 has added several new Modules: De-ess and Breath Control are broken out of the Leveler modules into separate modules with more comprehensive controls; Mouth De-click does the regular De-click one better, being targeted specifically to lipsmacks and other mouth-related clicks and noises; De-rustle and De-wind provide solutions for particular post production issues; Dialog Isolate pulls a voice up and/or out of a busy background; and De-bleed addresses that all-too-familiar problem of leakage, like from headphones worn during a recording. Each of these offers something specifically targeted to a particular problem so let’s take a quick look at them.
De-ess & Breath Control
In previous versions of RX, the Leveler module included simple ess-reduction and breath control options - basically just on-off and a sensitivity slider - but these new dedicated modules offer a lot more user control. De-ess provides settings for fine-tuning the frequency and speed of the de-essing, and it also offers a new Spectral De-essing mode, which applies spectral analysis and processing to the task of isolating and eliminating harsh sibilance. This can potentially make for more effective de-essing, with controls that allow the user to shape and tilt the spectral character of the sibilance, for more natural results. The new Breath Control module adds options for both amount of breath reduction and sensitivity to breath sounds, which seemed to me to isolate breaths even more precisely than the older version.
Mouth De-click
I’d never been able to get the regular De-click module in previous RX versions to reliably eliminate that problem on my own voice, but not only does the improved De-click do a better job, the dedicated Mouth De-click module works like a charm! Even at its default settings, this module seems to nail every bit of audio I’ve thrown at it, and it also provides additional controls to fine tune the detection and processing - whatever iZotope has done to tweak the general de-clicking algorithm to address dedicated mouth sounds, it seems to make a significant difference.
De-rustle & De-wind
These two are primarily for post production use, though of course they could come in handy on any application that suffers from those issues. De-rustle is aimed at removing or reducing the rustling sound of clothing rubbing up a lavalier mic. Like a number of the new modules, this addresses background noise that’s more irregular, and wouldn’t be handled as well by the standard De-noise modules, which do better learning & processing more steady, regular unwanted background sound. With a couple of files I threw at it, De-rustle was able to deal successfully with even fairly intrusive noise. A nice feature is an Ambience Preservation control, which allows De-rustle to remove rustling sounds while leaving other (possibly desirable) ambient sound intact.
De-wind addresses the problem of wind noise in outdoor recordings - the irregular and intrusive rumbling from wind shaking a mic’s diaphragm. With a couple of torture-test files I threw at it that suffered from especially loud wind noise, De-wind acquitted itself admirably - it should have no trouble with more typical subtle wind problems. A Fundamental Recovery control helps to restore any fullness in a voice lost to more aggressive processing, and Artifact Smoothing (a control common to many modules) helps to mitigate any hint of the watery-sounding artifact that sometimes accompanies this kind of FFT-based audio processing.
Dialog Isolate
This ambitious module lets you isolate a voice from background sound in a recording, or even vice-versa - pull a voice out of a recording, leaving just background sound (or music). Once again, unlike the existing Voice De-noise Module, Dialog isolate is tuned to be more effective with irregular background sound, rather than the regular noise the De-noise modules are designed to address.
And it works surprisingly well. I was able to substantially reduce the level of some especially intrusive background noise (subway train going by, loud voices is an ambient room), drawing out the primary voice until the background was, if not completely gone, largely unnoticeable; with less egregious examples of background sound, Dialog Isolate should be able to fully eliminate the undesirable noise. I wouldn’t necessarily expect it to be able to, say, completely lift a vocal out of a busy mix, especially one that’s somewhat buried in the mix, but considering how well it did isolating two voices (interviewer and subject) from background voices that were practically as loud as the main voices, it’s well worth trying on any recording - as with many of these processes, sometime multiple passes can provide an extra degree of effectiveness.
De-bleed
Finally, the new De-bleed module addresses the familiar issue of leakage, or bleed. As everyone knows, this can come from headphones during a recording (especially if a singer removes one earcup unnoticed, as they’re often inclined to do), in the form of the rough mix that was playing through the cans, or as the dreaded sound of a click track. Acoustic leakage, from other instruments in a live session, can also compromise the integrity of a track. But De-bleed can come to the rescue, if you’re careful to set it up properly..
De-bleed requires two files to do its thing: an “Active” track - the recording with the unwanted bleed - and a “Bleed Source” track - the track that contains the original audio that leaked into the Active track. For example, in a scenario with, say, an acoustic guitar recording that was cut to a click track in headphones, the guitar, naturally would be the Active track, and the original click track the Bleed Source. With a recording of a singer with bleed from a rough mix, the mix itself would be the Bleed Source. Both files must be loaded into RX6 (currently, De-bleed only works in the standalone version), and to be most effective, they need to be time-aligned. When I tested this, I bounced down the appropriate section of a leaked mix and lined it up with the vocal (which was an overdub) in the DAW, and then brought both files into the RX6 Advanced application.
And it worked! De-bleed Learned the profile of both tracks, and even though the bleed in my test file was quite loud (the singer had removed one earcup), and my Bleed Source mix file was not really the exact same rough mix as the one that had leaked into the vocal recording (I’d reconstructed it after-the-fact), De-bleed almost completely eliminated the leakage, especially under the vocal, where it really counted.
Wrap-up
So that’s what’s new and exciting in RX6 - while some of the new modules might seem at first glance to be merely refinements of existing features, in practice most offer significantly improved performance, along with much greater flexibility. And Dialog Isolate and De-bleed really do take audio repair to the next level. RX6 should be part of any audio engineer’s collection of tools, and with the various versions available, there’s no excuse not to have at least some of its features available for cleaning up your tracks and making them shine!
Price: RX6 Advanced: $1199 (regular); $799 (sale price)
RX6 Standard: $399 (regular); $299 (sale price)
RX6 Elements: $129 (regular); $99 (sale price)
RX Post Production Suite 2 (incl RX6 Adv): $1499 (regular); $999 (sale price)
Pros: Powerful collection of cutting edge tools for audio repair
Cons: Smaller/budget versions may omit that one feature you really wanted
Web:https://www.izotope.com/en/products/repair-and-edit/rx.html
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In its time, iZotope RX3 Advanced offered the most comprehensive suite of noise-reduction software—available as a stand-alone application and as bundled plug-ins—for post-production sound, along with extensive metering, time- and pitch-shifting processors, resampling facilities and other invaluable tools. RX 4 Advanced ($1,199) adds several workflow accelerators used to comply with various loudness standards and to quickly adjust level, timbre and ambience in tracks.
I reviewed Version 4.0.1 of RX 4 Advanced (its plug-ins in AU format) using Digital Performer V. 8.06 and an 8-core Mac Pro running OS X 10.9.5. For a refresher on RX 4 Advanced’s legacy features, check out my review of RX3 Advanced in the May 2014, issue of Mix.
Streamlined Interoperability
RX’s Spectral Repair plug-in—which was a bit of a kludge in previous releases—has been discontinued, made obsolete by the new RX Connect plug-in and alternative DAW interoperability. Roughly half of leading DAWs use RX Connect as a synchronized bridge to the stand-alone RX 4 Advanced application; you first select in your DAW the audio clip you wish to process, then launch RX Connect. Other DAWs (including DP) use RX 4 as an external editor: In DP, for example, you choose the RX application as DP’s external waveform editor and then open a region in RX via DP’s Audio menu.
No matter which protocol your DAW uses, after the RX application opens you can edit the selected clip using any processing (not just Spectral Repair) it provides. Different (fast and simple) methods are used, depending on your workstation, to return the processed clip back to your DAW in perfect sync with the original clip. Because some DAWs (including Pro Tools) monopolize the system’s audio drivers, an additional plug-in dubbed RX Monitor is included to enable hearing the RX application’s output; RX Monitor interacts with your DAW like an instrument to play the RX application’s audio through the DAW’s driver.
The updated Remove Hum plug-in and module—all modules belong to the standalone application—include an Adaptive mode that analyzes your audio and automatically notches out fundamental hum-related frequencies that change over time (such as in audio for a scene that was shot in multiple locations).
The updated Time & Pitch module provides an option to run Radius processing in real time, for those tasks in which you need fast processing. The tradeoff is lower quality than with offline processing (which is still available).
New Modules
The new Leveler module uses a compressor with automatic makeup gain to curb fluctuations in signal level. Use its Target RMS slider to adjust the K-weighted RMS level of your clip. The Speed slider alters how quickly gain is adjusted. Drag the Amount slider to limit the maximum amount of gain (boost or cut) that can be applied, and raise the Noise slider to reduce potential pumping when breathing or other broadband noise occurs during gaps in dialog. You can view the gain changes that Leveler applies and edit them by dragging up and down one or more nodes at once on a graphical curve (dubbed the Clip Gain envelope; see Figure 1).
The new Loudness module automatically applies a fixed amount of gain to your entire clip (or a selected region) to instantly make it comply with a specific standard, such as BS.1770, selected from a drop-down menu. Alternatively, you can use two sliders to manually set the desired loudness (in LKFS units) and maximum true peak level of the clip. A post-limiter is automatically applied as needed to meet the selected true-peak spec.
The new EQ Match module applies static equalization to purportedly make one region’s spectral balance conform to that of another. Simply select a region (such as a phrase in a VO track) that sounds great, click Learn, select another region that sounds bad, and click Process. EQ Match lets you save spectral profiles as presets, speeding your workflow.
The Ambience Match module does for noise what EQ Match does for timbre, with one caveat: It can’t decrease the amount of ambience that already exists in a selection; it can only increase it. This is an invaluable tool for matching an ADR track’s ambience to that of the recording being replaced. You simply make a selection of the noise in the live recording, click the module’s Learn button, make a selection in your ADR track where you want the same-quality noise added, drag the Trim control to adjust the level of the ambience to be added, and click Process. Noise snapshots can be saved as custom presets.
In Post-Production Sessions
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I used RX 4 Advanced extensively while working on five video projects containing many dialog tracks, music and B roll. The new Leveler module gave me excellent results easily and exceedingly fast, smoothing levels no matter the track’s spectral balance. It controlled boomy-sounding peaks beautifully, often precluding the need to de-boom using multiband compression. With moderate settings—the Amount control set no higher than 4 dB—I got more natural-sounding results than when using my go-to compressors and limiters. After rendering the processing, I could mouse-drag one or more nodes at once in the automatically generated clip-gain envelope to alter Leveler’s gain changes in select spots (see Fig. 1).
The Loudness module conformed my mix to any of seven different loudness standards with just a couple of mouse clicks—a real timesaver. Using the Ambience Match module, I could capture the room tone on a dialog track and add it to another track that sounded too dead; a trim control let me adjust the level of the ambience ±6 dB without affecting the level of the dialog. Listening to the generated ambience in isolation, it was apparent it was synthesized. But in the mix, it worked inconspicuously if applied sparingly to tracks in select, short gaps.
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I tried a couple dozen times to use EQ Match to smooth spectral balances on dialog tracks, but I always found I got better (and more predictable) results using a combination of static and dynamic equalization plug-ins.
Any editing performed on tracks in the RX application is destructive once sent back to DP (overwriting the original file everywhere it occurs in DP), a disadvantage compared to working with RX 4 Advanced’s nondestructive plug-ins. Overwritten files initially played back as—and looked like, in DP’s Sequence Editor—full-scale, broadband noise in DP; rebooting DP would always permanently restore pristine playback, but I’d sometimes also need to bounce the file to a new track to restore proper waveform display. This appears to be a bug in DP, not in the RX application.
On startup, the RX application would often arbitrarily reroute consistent output assignments to different MOTU I/O boxes or banks—sometimes to those disabled in the MOTU PCI Audio Setup utility. And I often heard distracting crackling noises and clicks while working with the application, especially while previewing a module’s processing. (An associate of mine confirmed hearing the same artifacts using RX 4 with a different system.) Thankfully, the artifacts did not print when files were overwritten back to DP; nor did they ever occur when using the RX plug-ins.
Purchase in Advance?
iZotope also offers a less-expensive “standard” version, which doesn’t include the Dereverb, Deconstruct, Leveler, Loudness, EQ Match, Ambience Match, Radius RT (Time & Pitch) and Insight (metering suite) modules and plug-ins. It also lacks the center-channel extraction and azimuth alignment features for the Channel Operations module and some extra controls for Denoiser, Spectral Repair and Declick. Many of these additional features included with the Advanced version have proven to be indispensible in my work; they are well worth the extra cost.
If you work in post-production sound, restoration or audio forensics and don’t already own RX3 Advanced, buying RX 4 Advanced is an absolute must—if only for its incredible legacy plug-ins. If you can tolerate the RX application’s intermittent routing and monitoring problems, the Leveler and Loudness modules make an upgrade from RX3 Advanced worthwhile.
Mix contributing editor Michael Cooper is a recording, mix, mastering and post-production engineer.
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DP can send only one region at a time to an external editor such as RX 4 Advanced. If you want to send an entire track containing non-contiguous soundbites, first make a time-range selection in DP for the entire track and select Merge Soundbites (option-shift-M).