There’s been a little controversy about the wording of this plug-in’s launch. At first glance it could be every home edit suite’s dream – clear, yet punchy audio, that’s still legal! Result!

Hmmm. Maybe not. Let’s take a closer look at what we have here.

iZotope describe RX Final Mix as, “a real-time plug-in for controlling your peaks and giving your mixes and sub-mixes a smooth sonic balance. The newest member of the RX family of post production tools, RX Final Mix plug-in is built specifically for audio post production professionals and video editors”, which can, “Ensure clearer dialogue, maximum sonic impact, and more accurate mix compliance”.

Audio professionals often have a low opinion of video editor’s audio expertise, so when a product such as this includes them in their target market, you can expect audio people to think it could be a “one- click-fix” plug-in that could put their income at risk.

But looking at the press release in more depth reveals that this a far more complex plug-in.

Firstly you have the Equaliser section. This is a 6 band (with low and high pass filters) dynamic EQ with automatable multiband compressor / expanders. You can drag the EQ band points around the screen and have them as dynamic or static. In dynamic mode they act like any dynamics section with a comp/exp would.

Then you have the True Peak Limiter, which can “legalise” your mix output. The enabling of the Equaliser and TPL are separate from each other, so you can use just one section, or both.

The Equaliser and TPL are mono to 7.1 compatible.

So, you can really fiddle to your heart’s content, insert it at any point, channel or bus, fully automate everything, and spend hours crafting the sound.

Or, you could punch up one of the presets. Which is what I started by doing.

I have an old session from “Plebs” Series 2 – 115 tracks for a half hour TV period sitcom. There was after all a chariot race at the end. Thanks to Rise Films for allowing us to use the “Plebs” clips. 

Here’s how it sounded using Avid EQ7, Avid DynDeEss, iZotope RX4 Advanced Dialogue DeNoiser and Avid Pro Compressor / Limiter

PLEASE NOTE ALL CLIPS CONTAIN LANGUAGE AND HUMOUR THAT MAY OFFEND

I then popped RXFM on to my Dialogue, Music and Effects stems. I selected a “Dialogue Enhance” on my Dialogue Stem,

A “Music Enhance” on my Music Stem,

And a “Sound Effects Clarity without harshness” on my Effects stem.

And got this result -

I am still using my Avid ProCompressor on the Dialogue Stem, to round off the dialogues in a pleasant way that isn’t crunched, but more amenable to being heard in noisy environments, and my AvidProLimiter on the master mix bus.

Personally I feel that it’s a subtle effect, but it is control-able. It sounds a little punchier and a bit brighter – does pretty much what it says on the tin.

I then thought to myself, “if you have the native processing headroom, and only want to treat parts of your say, dialogue stems, and not process everything, why not put a bunch of RXFMs on tracks rather than busses?”

So I did just that. In the first two examples I purposely left Cornelius’ (the chap with the sword) dialogue flat and muddy, to see if RXFM could dynamically adapt to the dialogue quality when on a bus. I didn’t think it was having a great success being left on a preset, on a bus, so I slung a load across my production dialogue. I then automated a custom multiband comp/exp setting to liven up his dialogue a bit and make it sound less like it is – a tiny mic taped to his chest.

This is the result –

So, you can also use RXFM as an insert on tracks as well as on busses, and get good results. This is the individual plug-in at work on his dialogue –

However, one thing we haven’t thought about yet is that “enhancement” can have an effect on the loudness figures. Peak levels are not the only tech spec we have to meet in broadcast, or in theatrical trailers and commercials. We have to meet EBU R128 on broadcast and LEQ(m) on theatrical trailers and commercials.

So let’s have a look at the loudness figures

So the loudness is slowly creeping up, but interestingly the loudness range stays the same for the first two clips, and widens slightly for the third.

Yes, none of them are EBU R128 compliant, but they are but two scenes from a half hour show, and that’s not how you mix a “legal” show – you don’t ensure that every scene is -23LUFS +- 1 – that is why there’s a loudness range measurement as well.

This makes me think that to get “broadcast legal” results, you would have to pair this plug-in with the RX Loudness Control plug-in.

I’ve tried the RXFM on 5.1 and 7.1 material, quite bombastic, and it does make everything somewhat leap off the screen and generally feels like it’s increasing the size of the room you’re in. I’m hoping that’s just an effect of the dynamic EQ, and not any phase irregularities. However it does have the same effect on loudness, so you have to revisit the mix if you have to be within loudness regs.

Summary

So in conclusion, I would call this an “Expert’s Precision Tool”. Any idiot can enhance the sound using this plug-in, but it takes an experienced idiot like me to get a result that’s both effective and legal, and to maybe think outside the box a little as to its usage.

Big thanks to iZotope for getting me the plug-in to review, and and especially big thank you to Rise Films for working hard to get the block on the YouTube content lifted for the “Plebs” clips.