Ozone 10/11 mastering assistant - questionable processing

[Opaque]

I'm copying here what I posted in r/audioengineering, since it didn't really trigger many responses. Btw, I do like Ozone and its modules, all of great quality, but the I'm really confused with the decisions on default suggestions given by the master assistant.


If possible I'd like to hear some opinions of professional mastering engineers regarding the way Ozone operates.

By default, when one lets the mastering assistant run, it creates a suggestion always using a huge number of these newer, specialized modules that rely on spectral and multiband processing. Now they've added even more stuff, in the form of stem separation, transient/sustain processing across all modules, and the clarity module.

Isn't all this spectral and multiband stuff bad by definition if it can otherwise be avoided, regardless of whether one can clearly hear the artifacts, phasing, etc. created by all this? It seems to me that, instead of trying to match the spectrum target using relatively minimal processing (eq, dynamic eq, compression, exciter), it will always overload the track with things like impact, clarity, stabilizer, spectral shaper, all using multiple bands and spectral mangling, which is especially weird when you see Jonathan Wyner and Em Mancini in their videos trying to use minimal processing, even explicitly avoiding using multiple bands where possible.

Isn't it a step backwards in some ways, increasingly becoming a track (bad mix) repair focused thing instead of just clean mastering, due to piling more and more spectral and multiband fuckery, which is essentially intended to reshape the entire track - and it does this always, as it is impossible, I believe, to request a suggestion/balancing with only selected modules?

[Jac459]

I am no expert but what make you think that spectral processing and multiband compression are bad by definition ?
The reasoning is odd to me. There is a difference between the heaviness of the processing you apply and the nature of the processing. As you mentioned yourself, even the people you named are using MB when it is necessary. It is a tool. And it is certainly a good tool when well used, at the right moment, when necessary. Likewise I don't see why spectral processing, when smartly and wisely used should be bad "by definition". Is it bad because it is new ?

[Frankie.T]

In my opinion Master Assistant it's a complete mess. All the decisions it makes, looks just a way to achieve a kind of model, that has nothing to do with the music.

It doesn't "listen to the song" trying to fixing the issues and enhance the music, but just follow the model he was written for.

This doesn't work with music, while it's just perfect for other situations.

If with Ozone v9 and older you could use assistant as starting point/suggestion, from v10 it's something to avoid

m2c ofc

[Opaque]

I am no expert but what make you think that spectral processing and multiband compression are bad by definition ?
The reasoning is odd to me. There is a difference between the heaviness of the processing you apply and the nature of the processing. As you mentioned yourself, even the people you named are using MB when it is necessary. It is a tool. And it is certainly a good tool when well used, at the right moment, when necessary. Likewise I don't see why spectral processing, when smartly and wisely used should be bad "by definition". Is it bad because it is new ?

No no, nothing to do with new or old, I am not a traditionalist by any margin, whether we're talking gear, songwriting, whatever. Also, if necessary I'm all for using whatever, and then those are all great tools and should be used, and the spectral stuff in Ozone is phenomenal.
But, as far as I know, using any form of spectral processing, separation by transients/sustain on the level of the entire track, especially when trying to process separate stems from a single stereo track, or simply creating crossover points for band separation (e.g. in multiband compression) always has some unwanted side-effects on the audio, whether they can be clearly heard or not.

Jonathan Wyner even explicitly states this in a number of their mastering videos, even in the latest mastering series that was published along Ozone 10 release:

Edit: timestamped links don't seem to work, watch 31:24 - 31:50
https://youtu.be/PKsAqmzn_ks?list=PL4dI ... yVC&t=1884

I know this isn't anything major, but it really makes no sense to me that with each new instance of Ozone, it seems to be doing more and more of that kind of stuff, piling up all kinds of multiband and spectral processing modules whenever you run the assistant.

[Jac459]

I am no expert but what make you think that spectral processing and multiband compression are bad by definition ?
The reasoning is odd to me. There is a difference between the heaviness of the processing you apply and the nature of the processing. As you mentioned yourself, even the people you named are using MB when it is necessary. It is a tool. And it is certainly a good tool when well used, at the right moment, when necessary. Likewise I don't see why spectral processing, when smartly and wisely used should be bad "by definition". Is it bad because it is new ?

No no, nothing to do with new or old, I am not a traditionalist by any margin, whether we're talking gear, songwriting, whatever. Also, if necessary I'm all for using whatever, and then those are all great tools and should be used, and the spectral stuff in Ozone is phenomenal.
But, as far as I know, using any form of spectral processing, separation by transients/sustain on the level of the entire track, especially when trying to process separate stems from a single stereo track, or simply creating crossover points for band separation (e.g. in multiband compression) always has some unwanted side-effects on the audio, whether they can be clearly heard or not.

Jonathan Wyner even explicitly states this in a number of their mastering videos, even in the latest mastering series that was published along Ozone 10 release:

Edit: timestamped links don't seem to work, watch 31:24 - 31:50
https://youtu.be/PKsAqmzn_ks?list=PL4dI ... yVC&t=1884

I know this isn't anything major, but it really makes no sense to me that with each new instance of Ozone, it seems to be doing more and more of that kind of stuff, piling up all kinds of multiband and spectral processing modules whenever you run the assistant.

Thanks for clarifying. Indeed, filtering can generate phase inversions for example, I see what you mean…

My personal understanding is that ozone offer great tools overal for professionals but also aims at helping beginners to create something more or less ok easily. Maybe they can be used by super advanced pro but they are in particular for the non-pro. Clarity on that aspects makes wonder in my opinion.
I guess if I was a seasoned multi gold record pro I’ll go more for non-bullshit fabfilter….

[Agg]

simply creating crossover points for band separation (e.g. in multiband compression) always has some unwanted side-effects on the audio, whether they can be clearly heard or not.

Jonathan Wyner even explicitly states this in a number of their mastering videos, even in the latest mastering series that was published along Ozone 10 release:

I don't necessarily like Izotope's business strategy with these features, but the statement about splitting bands is factually wrong (EDIT: assuming he says exactly what you said, I didn't watch the video). If the plugin works properly, splitting the bands does nothing, as the filters crossing over each other will cancel out the phase-shift. You can do a null test for free in Reaper, using the stock mb comp, probably in other daws too.

If you do something (such as compression) to any of the bands, then it's a different story.

[Frankie.T]

Afaik splitting band always bring differences even if there is no compression. You can split bands in 2 different modes. Linear Phase and Natural Phase.

While LP bring no phase shifting it introduce pre-ringing, then NP have no pre-ringing but introduce phase shifting.

None of them are good or bad, it just depends on the audio.
I don't think there is any multiband processor who doesn't change the audio in a way or in another, i think it's just not possible.

[rod_zero]

If you understand how machine learning works it would be obvious that companies as izotope simply doesn't have the data sets to train algorithms, I doubt any company in the audio software world has the data bases to do it.

In order to train an algorithm they would need a lot of observations of mastering chains per type of material (songs per genre), I really doubt they can make this data since it will require asking mastering engineers to master using just ozone and send the source material and the settings back, and they would need so many of this data points that I think it is totally unrealistic to do it right now.

So their claims about the usefulness of mastering assistant are greatly exaggerated and it is just a dumb algorithm with different settings for a given range of parameters it detects.

[discogsaddict]

Excellent set of tools if you know how and when to use them. But I do think the master assistant is a gimmick to jump on ai trends and appeal to users who want a magic mastering button.

I would guess the assistant is trying to shape mixes to fit their total balance control curves such as pop, edm, hip hop whilst at the same time make use of or show off, the latest modules.
If I had the time I would like to experiment feeding master assistant different mixes and try to figure out exactly what is going in. My guess would be regardless what you feed it, you will get the same modules loaded with slightly different settings (in order to fit those preset curves)

[Alexey Lukin]

Afaik splitting band always bring differences even if there is no compression. You can split bands in 2 different modes. Linear Phase and Natural Phase.
While LP bring no phase shifting it introduce pre-ringing, then NP have no pre-ringing but introduce phase shifting.

There are crossovers that don't change the signal (in absence of band processing) and there are crossovers that do. This property is called perfect reconstruction and it's not the same as linear phase. Ozone has both types.
The "Analog" mode uses nonlinear-phase filters and introduces some phase distortion (i.e., not perfect reconstruction).
The "Hybrid" mode (the default one) also uses nonlinear-phase filters, but has perfect reconstruction. I.e., when you mix the bands, you get the exact source signal.
The "Digital" mode uses linear-phase filters and also has perfect-reconstruction.

Your comment about pre-ringing makes sense when the bands are actually processed, e.g., compressed. That's where crossover starts having effect on the result: it could be either pre-ringing or phase distortion, depending on the filter type. But in the absence of any processing, many crossovers are completely transparent (just add latency).

[Frankie.T]

Afaik splitting band always bring differences even if there is no compression. You can split bands in 2 different modes. Linear Phase and Natural Phase.
While LP bring no phase shifting it introduce pre-ringing, then NP have no pre-ringing but introduce phase shifting.

There are crossovers that don't change the signal (in absence of band processing) and there are crossovers that do. This property is called perfect reconstruction and it's not the same as linear phase. Ozone has both types.
The "Analog" mode uses nonlinear-phase filters and introduces some phase distortion (i.e., not perfect reconstruction).
The "Hybrid" mode (the default one) also uses nonlinear-phase filters, but has perfect reconstruction. I.e., when you mix the bands, you get the exact source signal.
The "Digital" mode uses linear-phase filters and also has perfect-reconstruction.

Your comment about pre-ringing makes sense when the bands are actually processed, e.g., compressed. That's where crossover starts having effect on the result: it could be either pre-ringing or phase distortion, depending on the filter type. But in the absence of any processing, many crossovers are completely transparent (just add latency).

Never heard about "perfect-reconstruction". I'm not saying doesn't exist, don't get me wrong, i'm just very curious

Can you show me anything about that process? I'd like to see that mb processor in a null test

[Alexey Lukin]

You can easily try the null test with Ozone. Just make sure your crossovers are in Hybrid or Digital modes.

[Frankie.T]

You can easily try the null test with Ozone. Just make sure your crossovers are in Hybrid or Digital modes.

That's interesting!

I know this is "nerd time" cause trying with 2 different mb software with no processing where the second doesn't null just because have some differences under 200hz (it null completly over it) and i cannot really hear any difference soundwise.
So theoretically speaking this differences are something problematic? Or it's just like phase shifting, that doesn't mean good or bad, it just depends on the contest and sounds

[bpodolak]

I just tried it and got a perfect null. Might want to double check the setup

[Alexey Lukin]

In my tests the RMS of the diffs are roughly -150 dB below the original signal, so it's likely just a quantization noise.