Need tips for iZotope RX 2 to fix distortion in Interview

[Peter Groom]

ill have a listen in the studio tomorrow
Peter

Post Production Dubbing Mixer

[Peter Groom]

Hi
I had a listen and a play with noise reduction software, but with the time available I didnt manage to get rid of your distortion im afraid. Its pretty harsh in places.

To improve it a little with eq only try rolling off a little of the LF around @100hz and a little MID freq notch at about 1k with a Q of 1.0. And last drop off a little HF at 6k ish as the LF drop makes it sound a little bright in the balance. This reduces the noticability of the distortion, but doesnt remove it leaving everything else in tack, which is what i was hoping for.

There is a software called spectral Layers from Divide frame (now being distributed by Sony which might be worth a look. I dont have it (yet) but Im told its very good too. These restoration softwares are a steep learning curve. Im sure there will be a demo you can try it out on free?!

I think a specialist restoration engineer with tools like cedar might be able to do more for it. Depends on budget if youve got money to spend on the full fix. A specialist who spends their days doing this sort of thing will be able to get much better results than me because of practice, experience, tools and training.

Of course nothing is as good as getting the recording right in the 1st place!
Cheers
Peter

Post Production Dubbing Mixer

[Andreas Zuckerman]

Thanks a lot Peter, the result doesn’t have to be perfect at all so I’m sure your eq tips will do just fine.

It’s always hard to polish a turd 🙂

Thanks for having a listen

Cheers, Andreas

[Peter Groom]

Thats no problem.

Is also have a good look at the recording chain to find out where and why you ended up with the problem, to make sure it doesnt happen again.
We can and do ALL make mistakes, but not learning from them is daft.
Peter

Post Production Dubbing Mixer

[Tedd Terry]

Hi Andreas,

I work in iZotope’s QA department. Your distortion problem coincided nicely with some RX testing I was working on. I think I found a way to reduce the level of distortion in that file.

Step 1: Rotate the phase. Open Channel Operations, select the Phase Rotation tab, check ‘Vari phase rotation’ (the lazy way, you can probably find good settings by hand if that doesn’t work for you). This should change the waveform from being asymmetrical (mostly positive) to symmetrical. This will help our Declipper.

Step 2: Declip! This sounded like soft overmodulation of a mic pre, and you can see how some of the waveform peaks are squared off in the distorting parts. I set Declipper to Medium, Clipping Threshold to -11.6, and Makeup Gain to 0.0 (if that’s too hot for the entire interview, you may want to leave it at -6 (default) and adjust the gain later).

Here are my results:

https://www.mediafire.com/?y8bz2unyzq7neai

Not perfect, and maybe some artifacts from the waveform reconstruction declipper performs around 12.4 seconds where the distortion was very heavy, but certainly an improvement.

I hope that helps!