REPRINTED FROM OCTOBER 2004 WWW.PROAUDIOREVIEW.COM

Copyright 2004 JRS Publishing, Inc. Reprinted with permission.

BY ALAN SILVERMAN

Algorithmix is a German audio com-pany that has provided high-end dig-ital design for various audio equip-ment manufacturers and under-the-

hood DSP code for some of the world’s bestplug-in and workstation vendors. A few yearsago, under their own name, the companylaunched Sound Laundry, an inexpensive suiteof quality audio restoration tools. Now, withthe release of reNOVAtor, Algorithmix hasmoved to the head of the pack in high-resolu-tion audio repair and restoration with a prod-uct that is nothing short of amazing.

ReNOVAtor can remove extraneoussounds from a recording such as coughs, chairsqueaks, hits, cell phones, car horns, plosives,lip-smacks, sibilance, performance noises, etc,and it does it with remarkable speed, precisionand ease. After working with reNOVAtor for ashort while you quickly take audio fixes forgranted that were basically impossible untilnow. I am continually entertained by outburstsof surprise and enthusiasm on the part of otherengineers when I demonstrate reNOVAtor tothem for the first time. ReNOVAtor is tightlyintegrated into the workflow of the Sequoiaand Pyramix workstations, but the companyhas just released a PC standalone version ofthe plug-in.

FEATURES

ReNOVAtor begins by opening a new win-dow containing a three-dimensional frequen-cy-time-energy spectrogram derived fromFFT analysis of the audio to be processed.Frequency and time are shown on the verticaland horizontal axes, and energy is shown bycolor. Unwanted artifacts are then identifiableby sight. The more distinct the problems are

from the program, the easier they are to iden-tify. For disturbances that are visually less thanobvious, a variety of tools for refining theimage and real-time playback allow consider-able flexibility in separating the wheat fromthe chaff. Once a problem has been visuallyidentified, the user draws a rectangle around itwith the mouse, clicks the process button, and“poof” - problem gone.

ReNOVAtor applies intelligent interpola-tion that removes the unwanted sound andreplaces it with new sound resynthesizedfrom the region just before and after theselection rectangle. The surrounding materialis analyzed statistically for transient nature,

tempo, harmonics and noise to provide for abetter musical match. The results can beimmediately auditioned while still in the win-dow via real-time playback control. Undosare allowed, as are multiple passes, and dif-ferent sections of the window can be treatedsequentially.

When the results are satisfactory, the usercloses the window to find that the replacementmaterial has been automatically edited backinto the project with sample accuracy andmultichannel phase coherency. Any unpro-cessed audio is left unchanged and because anew clip is created, the original audio is neverlost. Of course, in many instances there is a lit-

Algorithmix reNOVAtor

Post

tle more to do than that, but in most cases that’sreally all there is to it. The process works at allsample rates up to 384 kHz and is therefore wellsuited for SACD and DVD-A production.

Beneath the spectrogram are two controlsections – one for the interpolator and one forthe display. The display color range, bright-ness and resonance are adjustable along withindependent horizontal and vertical zooms.Both a logarithmic and a linear view areavailable for the frequency axis. The channelview can be set to left, right or left+right or,in the Pyramix version, the display can betoggled across a multitrack group. (Multipletracks can also be processed in Sequoia, butthe display is limited to whichever pair is lastselected.) When performing processing onmultitrack groups there is no phase shiftintroduced between tracks. The most signifi-cant display parameter is the FFT block size,ranging from 32 to 8192. The smaller theblock size, the higher the time resolution, sosmaller values are best for tics and clicks.Conversely, longer block sizes increase reso-lution at low frequencies and are best suitedfor treating bumps, thumps, plosives andrumbles. All or part of the audio in the win-dow can be played at will, including pro-cessed and unprocessed sections. This fea-ture along with undo makes reNOVAtorespecially easy to work with.

The interpolator can be tweaked in a vari-ety of ways. Overall accuracy is set with the“order” parameter with a correspondingtradeoff in processing time. Even set at itslowest (fastest) value the audio quality of theinterpolation is excellent at all frequencies.The channels to be processed are selectableas well as the type of interpolation to beapplied. The interpolation types offered arehorizontal (time) and vertical (frequency)plus variations which can force the directionof the interpolation if need be. There is alsoa 2-dim type that is specifically for veryshort artifacts and, unique to reNOVAtor, avery effective “gain selective” type. Gainselective interpolation allows the process toaffect the selected material only in anadjustable amplitude range and leads tosome very intriguing applications.

IN USE

My first application of reNOVAtor cameduring the mastering of a jazz violin andpiano duet. The violinist had played a near

perfect solo except for an annoying bowscrape during a long sustained note. Sheasked if anything could be done. My firstthought was to say no and move on, but I hadjust received a license for the plug and some-what hesitatingly decided to give it a try. Ihad only skimmed through the quick starttutorial and I did not want to fumble aroundin front of a client. In spite of my lack ofexperience, I found the process to be fast,intuitive and user friendly. The dissonantharmonics were visible in the spectrogramwithout any adjustment of the default win-dow other than the vertical zoom. I drew therectangle, clicked process, and auditionedthe results. The scrape was gone, the propernote remained, and the only extraneoussound was that of our jaws dropping. Thiswas impossible. I only had to raise the levelof the replacement audio a bit to match.

The next trial occurred during a countrymastering session. In this case, a fine acousticguitar solo was practically ruined with a fret-board squeak that smacked you hard in theforehead. Ordinarily something like that is anorganic part of a performance and you leave itand love it, but this one was over the top. Aminute later it was as though it never hap-pened. I have since found that going toreNOVAtor is the fastest and cleanest way todeal with plosives, lip smacks, and studioclinks and clanks.

Coughs picked up during live performancerecordings are a lot more difficult to deal with,especially when they are splashed in reverb ornatural ambience. In dealing with these I findthat multiple passes are generally required,

working first on the highs, then the lows, andthen the reverb tail to get the best results.Display adjustments are essential to findingthe right areas to work on and a fair amount oftrial and error is required. Because reNOVAtorallows you to audition and undo each stepwhile in the window, the time there is spentvery efficiently. A little of the cough usuallyremains at the end of the treatment, but movedfrom front row center to the balcony.

I do a fair amount of work on material thatoriginates on optical sound tracks and 78 rpmtranscriptions and find the Algorithmix processvery well suited to dealing with rocks, pops,snaps and sibilant distortion. In the latter case,the plug’s gain selection mode is essentialbecause some sibilance needs to be retained.

A few of us who are reNOVAtor users havetaken to calling each other at odd hours tobrag. After all, who else can you talk to aboutthis stuff? I received a call from my friendGraemme Browne of Zen Mastering inVancouver that wins the prize. Graemme wasmastering the final 5.1 live surround mix of anine-voice women’s choir in which one of thesopranos kept jumping out on specific notes.Working in Pyramix, and applyingreNOVAtor’s gain-section mode, he was ableto rebalance each occurrence of the obtrusivenote simultaneously in all five of the mainchannels by lowering its level and sweeteningits sound by reducing some of its harmonics.Now, that is a Zen Master.

SUMMARY

Algorithmix makes me a genius.ReNOVAtor continues to surprise anddelight. Each time I’ve put it up against aproblem that until now would have requiredconsiderable time to achieve only modestimprovement, it has made short work of thesituation with perfect or near perfect results.New applications are continually presentingthemselves. I cannot see how reNOVAtor isanything less than an essential tool for theaudio professional dealing with the kinds ofmajor disturbances routinely found in finish-ing sound for film, television and records.Disturbances that would mar a beautiful per-formance or an otherwise perfect recordingbecome ancient history.

Alan Silverman, formerly an engineer atthe late, great A&R Recording, is founder ofArf! Digital, a 96/24 and 5.1 mastering facili-ty in NYC; www.arfdigital.com.

Copyright 2004 JRS Publishing, Inc. Reprinted with permission. Reprinted from Pro Audio Review

Fast Facts■ Applications:

Post production, studio High-resolution audio repair andrestoration

■ Key Features: Noise analysis and removal;frequency-time-energyspectrograms; up to 384 kHzsample rate; multiple undo

■ Price: $2,490, €2,490

■ Contact: Algorithmix at +49 7741-91930,www.algorithmix.com.