Zaxcom's NeverClip explained

[Christian Spaeth]

You get additional headroom above the 0 dB FS representation of the meter. It is 20 dB when mixing with the faders. It is what ever the iso attenuation is when sending pre fader iso tracks to recorded tracks.

Now I'm confused. So the ISO meters show the levels without attenuation (hence the addtl. headroom right to 0), but the card meters do show the attenuated signal. Is that correct?

[Mark Orusa]

There are no ISO meters. If you have ISO attenuation applied you can seeing the result of that on the card tracks. My understanding of Glenn's statement is that you can't see the entirety of a NeverClip input on the input meters.

 

I've often found that if I can't understand something it's either because it's way over my head or it just doesn't make sense. US Taxes don't make sense, so I hire a certified professional accountant (CPA) to do them for me. I'm smart enough to understand audio, so...

 

Mark O.

[Christian Spaeth]

right, input meters is what I meant. Makes sense now after having had lunch and reading it again.

[glenn]

All meters show the actual levels of all inputs, outputs and card tracks at all times.

 

If you use 12 dB of ISO attenuation the card track meter will show its actual level that is 12dB lower than it would be without ISO attenuation. This ISO card track would have 32dB of headroom.

 

Glenn

[Mark Orusa]

All meters show the actual levels of all inputs, outputs and card tracks at all times.

 

If you use 12 dB of ISO attenuation the card track meter will show its actual level that is 12dB lower than it would be without ISO attenuation. This ISO card track would have 32dB of headroom.

 

Glenn

So if I have a signal that approaches the top of the input meter, but doesn't hit the 0 dbFS limit, would there be any need for ISO attenuation?

 

What do you mean the card track will have headroom? Headroom is usually in reference to microphone head amp gain. I always try to keep a card track signal comfortably as close to 0 dbFS as possible without limiting or clipping. If my input signal is near the top of it's meter, it should be near the top of the card track meter too. Isn't there a 1:1 relationship there?

 

Mark O.

[Jeff Wexler]

"As I said in a previous thread, if you are mixing at appropriate levels, regardless of whether or not you are taking advantage of NeverClip ISO, life will go on as usual.

 

Please excuse my frustration,

 

Mark O."

 

You actually should be able to "attenuate" your own frustration if you would repeat the above to yourself again. Using NeverClip does not require you to change anything about the way you work, your gain settings, your diligent attention to level, etc. What it does do is SAVE you from the unexpected level or excessive dynamic range that would in almost all other circumstances produce distorsion, clipping, or other unwanted and problematic sound. No need to start worrying about re-calibrating meters, wondering about these things that you say are happening in the "mysterious land". Even as well versed as you are with "the numbers", there are all sorts of things happening under the hood every second with every device we use and there is not the necessity to look at or keep track of every single number or calculation. This is just my own personal take on all of this and it comes from my own long standing perspective on the necessary balance in our work between understanding completely the physics vs. listening.

[Mark Orusa]

Yes, I will continue to work as I have. I don't need NeverClip ISO because I know how to moderate my audio levels. NeverClip for me is just a dual A/D converter with a name.

 

Mark O.

[Jeff Wexler]

Well, Mark, you're a better man than most, with a degree of confidence that is enviable. No one "needs" NeverClip but since it is free, always working and doesn't require any change to your (brilliant) workflow, but the first time it saves someone it will be appreciated and respected (possibly even by you). I will add that in the work I do, for the last 43 years, I can count on one hand the number of times I have made a recording that has any distorsion on it, but hey, that's just me (possibly I too have learned to "moderate my audio levels"). Just because you or I don't need it in the work we do doesn't make it a useless feature "with a name". I think NeverClip (or whatever you want to call it, or not even talk about it having a name) is pretty amazing accomplishment. Other manufacturers who do not have this "dual A/D converter with a name" are more than ready to declare that they don't have it because nobody needs it. Fine. Again, we make our choices, and I would most probably choose to have a device with an input that can handle a signal with dynamic range approaching the limits of the industry standard 24-bit file without the use of limiting or compression.

[Mark Orusa]

Jeff, I'm asking detailed questions earnestly trying to get a better understanding of NeverClip and NeverClip ISO. The more I dig, the more I come to understand that it's true benefits appear shrouded in mystery and confusion. If you don't want me asking my questions here then I will stop.

 

Mark O.

[Jeff Wexler]

I'm completely on board with your asking the questions --- I am a firm believer in developing an understanding of the things up to the level that makes us comfortable. I realize that in your case, this is a level of specificity that is probably higher than that which others may require. No harm in exploring and asking the questions here. What I am not a big fan of, and there has been a fair amount of this in this thread, is that if YOU don't understand it, it probably doesn't work. My objection is not to your personal quest to thoroughly understand NeverClip, this is admirable, it is the dismissive statements made right in the middle of this quest for explanation. Things like:

 

"I don't need NeverClip ISO because I know how to moderate my audio levels. NeverClip for me is just a dual A/D converter with a name."

 

This statement actually negates the lofty goal of your stated quest to understand NeverClip because YOU don't need it. Implicit in this dismissive statement is that NeverClip is a useless feature with a clever name. If this were even slightly true, why all the detailed previous posts asking all the questions, trying to "understand" NeverClip, etc., etc.?

[rb1138]

Wouldn't it be better to put something like neverclip on the quiet end of the volume and not at the loud end?

 

I've always wondered since back at film school about why we always have to play with the pots at all. Something about too much signal-to-hiss. Something about too few bits. If something like neverclip could automatically bring signal that goes to low up to normal it would probably have the same benefit. Maybe we could turn all the knobs down. We'd never have to clip.

 

Any thoughts? Maybe something at both ends?

 

Material that goes to the recorder (even if the recorder is Zaxcom) that exceeds 0 dbfs still clips, doesn't it?

 

 

 

 

Sawrab

[cinetj]

So if I have a signal that approaches the top of the input meter, but doesn't hit the 0 dbFS limit, would there be any need for ISO attenuation?

 

What do you mean the card track will have headroom? Headroom is usually in reference to microphone head amp gain. I always try to keep a card track signal comfortably as close to 0 dbFS as possible without limiting or clipping. If my input signal is near the top of it's meter, it should be near the top of the card track meter too. Isn't there a 1:1 relationship there?

 

Mark O.

 

From Wikipedia: "In digital and analog audio, headroom is the amount by which the signal-handling capabilities of an audio system exceed a designated level known as Permitted Maximum Level (PML). Headroom can be thought of as a safety zone allowing transient audio peaks to exceed the PML without exceeding the signal capabilities of an audio system (digital clipping, for example). Various standards bodies recommend various levels as Permitted Maximum Level."

 

For me the key to understand Neverclip is to think dynamic range as a two way street. If we, with the extra headroom given by the dual A/D converter, can't go beyond 0 dbfs to take advantage of this extended dynamic range, we go down with the attenuated ISOs, plain and simple. And we can go now way under without adding noise to the track - a two way street as I said.

 

In my opinion, this doesn't have to change the way we work; we can set our levels as always. And I agree that would be even more practical that way since we wouldn't have to add any gain at post. A nice use for NeverClip could be as a second backup track for your hardwired mic. 

[Christian Spaeth]

The only problem, or downside if you will, I have with NeverClip ISO (and I'm pretty sure others have too) is that post would have to bring up all the levels for the tracks where the signal did not go "beyond 0 dBFS". I just don't see it becoming a standard practice and workflow, since different mixers use different recorders, some have NCISO, others don't. Plus, if I use different levels of attenuation, I am sure this would cause too much confusion.

 

Here's a thought: For all the recorded tracks that did not exceed 0dBFS, what if the recorder (the Nomad in this case) automatically brought the levels back up by the amount of attenuation, after each recording has finished. Don't know if this is technically possible, but this would result in files with the same levels as always, with the only exception being that the few files that did go beyond 0dBFS and without NCISO would distort or clip, now instead are attenuated and clean. That way nobody would even have to know about Neverclip and everybody would be happy and everything would be better. THEN, there would be no downside. What do you think?

[soundslikejustin]

The only problem, or downside if you will, I have with NeverClip ISO (and I'm pretty sure others have too) is that post would have to bring up all the levels for the tracks where the signal did not go "beyond 0 dBFS". I just don't see it becoming a standard practice and workflow, since different mixers use different recorders, some have NCISO, others don't. Plus, if I use different levels of attenuation, I am sure this would cause too much confusion.

Here's a thought: For all the recorded tracks that did not exceed 0dBFS, what if the recorder (the Nomad in this case) automatically brought the levels back up by the amount of attenuation, after each recording has finished. Don't know if this is technically possible, but this would result in files with the same levels as always, with the only exception being that the few files that did go beyond 0dBFS and without NCISO would distort or clip, now instead are attenuated and clean. That way nobody would even have to know about Neverclip and everybody would be happy and everything would be better. THEN, there would be no downside. What do you think?

So, normalizing? It would not work in the way you expect.

Say for example, you're using NeverClip with an ISO attenuation level of -6dB. Now, your average dialogue level is reduced 6dB as well ie if your average dialogue peaked between -20 and -16, it now peaks between -26 and -22.

Now you have an unexpected peak come in, that goes 5dB above the input/output 0dB level, NeverClip does its thing and brings it in clean. It travels through the mixer in 32bit mix land, and hits the card track, where it is attenuated by 6dB. Result: a lower than normal dialogue level, and a peak level of -1dB. Normalizing the file in Nomad could only lift the entire file up to 0dB, as adding the whole 6dB would lead to 5dB of over level.

Instead, in post, they can do volume automation, or now Clip Gain to only boost the low parts (where the dialogue is sitting 6dB lower than it normally would) of the file, and leave the peaks alone. Alternatively, they can lift the whole file because they're probably mixing in 32bit, have the necessary headroom to deal with it and can either cut it out, compress it or do a fader move to deal with that peak.

[soundslikejustin]

Wouldn't it be better to put something like neverclip on the quiet end of the volume and not at the loud end?

Call it NeverTooLow? What you're describing here is exactly what AutoGain is and why it sounds so bad. It lifts the audio to what it thinks is a decent level, but when doing this to a quiet source and then a loud peak...it sounds rubbish.

[Chris Woodcock]

I've always wondered since back at film school about why we always have to play with the pots at all.

Sawrab

God forbid actually getting paid to be a mixer.

[soundslikejustin]

God forbid actually getting paid to be a mixer.

hahahaha.

[rb1138]

God forbid actually getting paid to be a mixer.

The range that we're supposed to mix in is always suspiciously narrow.

Call it NeverTooLow? What you're describing here is exactly what AutoGain is and why it sounds so bad. It lifts the audio to what it thinks is a defen level, but when doing this to a quiet source and then a loud peak...it sounds rubbish.

Reading some of the recent posts before ours, I think NeverClip may do what I was thinking of, without any lame autogaining. "Attenuation" sounds a lot like it.

Sawrab

[Christian Spaeth]

So, normalizing? It would not work in the way you expect.

Say for example, you're using NeverClip with an ISO attenuation level of -6dB. Now, your average dialogue level is reduced 6dB as well ie if your average dialogue peaked between -20 and -16, it now peaks between -26 and -22.

Now you have an unexpected peak come in, that goes 5dB above the input/output 0dB level, NeverClip does its thing and brings it in clean. It travels through the mixer in 32bit mix land, and hits the card track, where it is attenuated by 6dB. Result: a lower than normal dialogue level, and a peak level of -1dB. Normalizing the file in Nomad could only lift the entire file up to 0dB, as adding the whole 6dB would lead to 5dB of over level.

Instead, in post, they can do volume automation, or now Clip Gain to only boost the low parts (where the dialogue is sitting 6dB lower than it normally would) of the file, and leave the peaks alone. Alternatively, they can lift the whole file because they're probably mixing in 32bit, have the necessary headroom to deal with it and can either cut it out, compress it or do a fader move to deal with that peak.

 

You didn't get me right. It wouldn't be normalizing. That would not be very intelligent. I wrote that only when a peak goes beyond 0dBFS (not counting in the attenuation, at whatever value it is set), the according track would stay attenuated, thus preserving the dynamic range (and of course resultng in a lower general level than the other tracks). So in your example the track would still peak at -1dB. For all the other tracks, the attenuation would be "undone" after recording stops (because it wasn't needed). For post, dealing with one track that is mixed at a lower level than the others once in a while is less of a deal than having to make up different amounts of gain on some tracks and none on others, depending which ones were attenuated and if so, by which value. I think this idea would work, but of course the question is if it is technically possible to automatically "undo" the ISO attenuation within the recorder.

As things are now, the way I see it is you have to use always the same amount of ISO attenuation on all of your tracks in order to prevent confusion in post.

[Constantin]

I don't get it. On a non-never-clip machine, what do you do in a very dynamic scene, where someone whispers then shouts? You either bring down the gain for the entire scene, or just for the loud part. In the first case, post will have to bring it all back up again, and do sonething to the loud part so that it fits well. Same goes for NeverClip. I don't see a problem. It's the mixer's choice which way he does it. In the second case, by the way, post would not have to bring any levels back up, but dynamic range would have been lost.

[rb1138]

This may be a stupid question. What exactly are the "card meters" vs the ISO meters? 

 

 

 

Sawrab

[Chris Woodcock]

This may be a stupid question. What exactly are the "card meters" vs the ISO meters?

Sawrab

Same thing

When people say ISO meter they are referring to the card track that has the neverclip iso attenuation

[rb1138]

But they just mean it in terms of sequence right? When it becomes a card track it's already recorded? Thus why you can't see the attenuation in the normal ISO meters? 

[Chris Woodcock]

But they just mean it in terms of sequence right? When it becomes a card track it's already recorded? Thus why you can't see the attenuation in the normal ISO meters?

The card track is the meter for anything being sent to the cards forget the term iso track

[rb1138]

The card track is the meter for anything being sent to the cards forget the term iso track

 

Okay!

 

 

NeverClip definitely seems like a positive to me. Definitely getting a Nomad when I can finally upgrade. 

 

Glenn explains NeverClip in of this thread pretty well. 

 

 

Sawrab