iZotope RX Mastering Tips

10 Common Uses for Audio Restoration in Mastering

4. Removing unwanted distortion Every once and a while you get a project that has audible distortion. It could be undesirable clipping, or it could be something else entirely. All you know, from your vantage point, is that the distortion is undesirable to you.

But it might not be undesirable to the band. Your first move is to call the point person on the production team and ask if that distortion is intended. If it isn’t, your next move is to contact the engineer, if you can, and negotiate a better mix. This option isn’t always on the table, so luckily software like RX has ways to fight this distortion—tools which can, to some extent, repair mangled material.

A lot of the time the De-clip module does the trick, even if the material isn’t clipping per se. The process is relatively simple: highlight the passage that is distorting, have the module suggest its processing, audition the results, and tinker to taste.

Repairing distortion is best done in specific, sporadic places, and not across passages of more than a couple of seconds—and that’s speaking liberally. You may have to spend a bit of time to get all the nasty bits, but it’s still worth it.

Sometimes, the distortion is more of a high-end crackle than a clip. Here, the De-crackle module, tuned to attenuate high-frequency distortions, can often work.

I have a very particular live performance in mind. Recorded a guitar (DI) that was using some form of distortion — pedal or amp, not sure. Unfortunately detracts from some of the songs, can’t really remove the guitar. My case isn’t mastering, I have an isolated track. Need to try the “De-crackle” and “De-clip”. The track(s) don’t clip. Challenging.

Applying in practice. As I suspected the De-clip module doesn’t touch the distorted audio. The clipping got recorded at about -12 dB soooo.

De-crackle made a nice dent in the scratchy top-end of the distortion. Basically maxed out the settings, soloed the crackles, made things better. Nice to know.

Sonarworks Love

I need to add some love to the Sonarworks world.

I have lived in the world of IK/Multimedia ARC 2 (Automatic Room Correction) for about 3 years. Changed my world. A lot. No complaints. Separate profiles for my JBL LSR305, M-Audio AV-40, Casio PX-330 piano (has line in so I can work with the piano but have all the sounds).

Decided to try Sonarworks for headphones on the laptop…was impressed with the demo. Impressed enough to purchase the headphone license. Then we get the PLAPA discount, so I decided to go for the full Reference 4 upgrade. It’s November — studio upgrade season. Tried really hard to build room profiles using my reference mic from ARC2. That was an abject failure. OK…I’ll get the Sonarworks microphone and do the whole thing.


I “shot the room” this afternoon. Took a bit of fooling around to get a proper level so I could calibrate. When the software told me how far apart my speakers were to the half-inch I was excited to proceed. Many measurements. I got good by the end and could put the mic almost exactly where the software wanted it.

Now I get to listen to music for a couple of weeks to re-train my ears 😉 Definitely a different adjustment than ARC2. Bass is way more in control. My “Mix Test” doesn’t get the whole house vibrating anymore on the dub music. The boomy jazz bass is still very bass present, but the fretboard sound is quite “visible” and no longer lost.

I’m really buzzed about the loss of the buzzy-room bass…really.

Happily I can flip between ARC2 and Reference 4 without much difficulty — mad skillz ya know…

So far I have gone more than an hour at full reference volume on the mix test without running out of the room 😉 SPL meter is reading the same as always — 74 dB for most things, 85 dB for the ZZ Top and Conspirator.

Time to let the ears rest…little bit of Robert Jon & The Wreck 😉 I turned it down…

Lifetime Member — Produce Like a Pro Academy

Simple. No-brainer. They offered a lifetime for the price of 2 years. Who am I to turn this down? I was ready to sign up for year 2 after about a month of wandering the forums, classrooms, and workbooks.