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Author Topic: Digital tracking with low levels = better...is this new???  (Read 125546 times)

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Re: Digital tracking with low levels = better...is this new???
« Reply #30 on: January 11, 2007, 03:04:42 pm »

compasspnt wrote on Thu, 11 January 2007 09:39

And surely no one in today's climate is concerned with KEEPING maximum dynamic range anyway!

Seriously, if, instead of 144 dB DR, you have ONLY 132, yet at the same time you are virtually eliminating digital distortion, whilst reducing the "artifacts" commonly associated with digital recording, I think you're still doing "real good."



Considering most rock records today during heavy spots have about 9 DB of range after being "stunned", this amount of dynamic range may seem strangely pleasant and punchy...drums may punch! Solos may soar! There will be space and wide dimensions! Write home to Mom!

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compasspnt

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Re: Digital tracking with low levels = better...is this new???
« Reply #31 on: January 11, 2007, 03:27:28 pm »

Actually, to answer Michael's original question...

Digital tracking with low levels = better...is this new???

In a way, I guess that here, at WW, and Reason, and PSW in general, it is new.
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Kendrix

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Re: Digital tracking with low levels = better...is this new???
« Reply #32 on: January 11, 2007, 03:29:22 pm »

Tomas Danko wrote on Thu, 11 January 2007 20:00

Kendrix wrote on Thu, 11 January 2007 17:28

CHANCE wrote on Thu, 11 January 2007 16:07

You lost me. How would you lose dynamic range? Recording at lower levels, the relative differences between 0db and your highest level will still be the same yes?


I think not.- You are effectively reducing the "highest level" by recording at a lower volume.  So, dynamic range is reduced.

If you A to D convert into a 24 bits and you turn the input or trim down so that you record say 12db below where you'd be if you peaked at zero then you are reducing the dynamic range of the signal being converted by 12db.  In doing so you are using 2 fewer bits than are available.  

The point is that the quality of the subsequently reconstructed waveform (after the D to A) does not suffer when you do this.
Since virtually any real sound source hs much less than 144db dynamic range you really dont lose anything- however you gain the benefit of digital headroom when summing.



Not really.

The sound you record will live roughly somewhere below the incoming noise floor (ie background noise, microphone, preamp and so forth) up to the maximum peak of the sound in question.

It will most definitely be able to live between 0 dBFS and, say, -144 dBu.

Now, if you set your A-D converter to only peak at -12 dBu you will still be recording the entire dynamical span of that sound set lower within that 24 bit file.

So practically speaking, if something had, say 80 dB of total dynamic range then you can decide to record it into 0 dBFS and downwards or you could record it into -12 dBu and downwards.

Align the recordings by shifting the mantissa up or down (ie within a 32 bit floating point register) and you'll see it's all there regardless of how hot you printed it.

The difference is that if you slammed the converter there are some penalties to be had regarding the analog front end of the converter, the decimation process in it. And even more so, downstream when you apply plug-ins and a mixing engine.

That just about sums it up.

Regards,

Tomas Danko


I understand the distinction you are making between available dynamic range of the medium and the actual dyunamic range of the signal you place on that medium.  I agree.

However, if you turn the amplitude of an incoming signal down to zero you have zero dynamic range.  If you fully modulate a signal having 100 db of dynamic range then you've got 100db.  Modulate to 50% and you have reduced the range accordingly.  So, doesnt it follow that by reducing the amplitude of the incoming signal so that it to sits at -12 verus zero you have reduced its dynamic range?  That was my point.
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compasspnt

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Re: Digital tracking with low levels = better...is this new???
« Reply #33 on: January 11, 2007, 03:31:03 pm »

Academic argument.
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maxim

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Re: Digital tracking with low levels = better...is this new???
« Reply #34 on: January 11, 2007, 07:02:08 pm »

the worst kind...
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Tomas Danko

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Re: Digital tracking with low levels = better...is this new???
« Reply #35 on: January 11, 2007, 07:12:33 pm »

Kendrix wrote on Thu, 11 January 2007 20:29


I understand the distinction you are making between available dynamic range of the medium and the actual dyunamic range of the signal you place on that medium.  I agree.

However, if you turn the amplitude of an incoming signal down to zero you have zero dynamic range.  If you fully modulate a signal having 100 db of dynamic range then you've got 100db.  Modulate to 50% and you have reduced the range accordingly.  So, doesnt it follow that by reducing the amplitude of the incoming signal so that it to sits at -12 verus zero you have reduced its dynamic range?  That was my point.



The cool thing is that within a 24 bit system you can slide that 100 dBu-range recording up and down... say... 44 dBu down from the dreadful zero and still have full dynamics. Smile

Practically speaking that's not the most common thing to record, and also practically speaking those 44 dBu will be diminished somewhat due to the inherent s/n ratio of the converters.

Still, lowering the maximum peak will not reduce the overall dynamics in a 24 bit digital recording system.
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Kendrix

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Re: Digital tracking with low levels = better...is this new???
« Reply #36 on: January 11, 2007, 09:23:21 pm »

Tomas Danko wrote on Fri, 12 January 2007 00:12

Kendrix wrote on Thu, 11 January 2007 20:29


I understand the distinction you are making between available dynamic range of the medium and the actual dyunamic range of the signal you place on that medium.  I agree.

However, if you turn the amplitude of an incoming signal down to zero you have zero dynamic range.  If you fully modulate a signal having 100 db of dynamic range then you've got 100db.  Modulate to 50% and you have reduced the range accordingly.  So, doesnt it follow that by reducing the amplitude of the incoming signal so that it to sits at -12 verus zero you have reduced its dynamic range?  That was my point.



The cool thing is that within a 24 bit system you can slide that 100 dBu-range recording up and down... say... 44 dBu down from the dreadful zero and still have full dynamics. Smile

Practically speaking that's not the most common thing to record, and also practically speaking those 44 dBu will be diminished somewhat due to the inherent s/n ratio of the converters.

Still, lowering the maximum peak will not reduce the overall dynamics in a 24 bit digital recording system.


Now I understand your point Tomas. Thanks.

Yes... pulling the track fader down after conversion to generate any needed headroom on the summing bus wont reduce the dynamic range of a typical real world signal in a 24 bit system.

This may be prefereable to reducing the amplitude of the incoming analog signal hiting the A>D converter. In that case you are reducing the dynamic range of that signal. However, you do not impact the quality of the reconstructed waveform.  That was my point.  In this case, if you manage to leave the fader at zero gain you avoid any potential artifacts of the digital math involved on that fader (most relevant if floating point math is NOT used).

I suspect the best approach depends on the specific situation.
With the best available converters and floating point math Id suppose full range conversion and a subsequent track fader reduction might be the way to go.  

In the real-world I usually end up somehere in the middle...both
trimming the input upon conversion if required to get close and using modest fader gain reduction at mix time.

I sure hope this got us out of the "academic" doghouse Very Happy






 
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Ken Favata

Tomas Danko

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Re: Digital tracking with low levels = better...is this new???
« Reply #37 on: January 11, 2007, 10:09:53 pm »

Kendrix wrote on Fri, 12 January 2007 02:23


I sure hope this got us out of the "academic" doghouse Very Happy



Theoretically speaking, yes.  Cool wouf wouf

Regards,

Tomas Danko
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Extreme Mixing

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Re: Digital tracking with low levels = better...is this new???
« Reply #38 on: January 11, 2007, 10:54:33 pm »

Music sounds better when recorded at lower levels.  I think that's mostly a function of the A/D converters and the preamps and compressors that we use on the front end.  They are meant to work best around 0 VU.  To get the level to digital zero, you may have to push your trusty neve up to +25 or 30; something it was never intended to do.  

From a practical point of view, when mixing in the computer, it really helps to have your faders in a place where you can easily make sublte moves.  Having the fader around unity is the best place.  Try making a .5 db move there, then try the same .5 db move with the fader at -30.

My advice is to read the thread with Paul Frindle, and the others for a full explaination of what's going on behind the curtain.  Digi also has a white paper on the DUC that is helpful.  Do what you think is best, but don't fall into the "use all the bits for best resolution" trap.  I think it's the same style of logic that President Bush is using for his Iraq strategy!

By that way, what ever happened to Nika?  Did he go back to school or take a job somewhere?  He was such a bright guy!  It was always a great learning experience to have him jump into these discussions.

Steve

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Re: Digital tracking with low levels = better...is this new???
« Reply #39 on: January 12, 2007, 04:37:32 pm »

Someone please be more informative on the subject.
What's the problem if i'm peaking at -1db per track,plug-in (in-out),aux,group or per master track??? I think they're all designed to clip >0,right? Confused
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compasspnt

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Re: Digital tracking with low levels = better...is this new???
« Reply #40 on: January 12, 2007, 04:40:15 pm »

Haris, read the thread

http://recforums.prosoundweb.com/index.php/f/29/6490/

in its entirety.  Pay especial attention to the last 9-10 pages.

Then if you still have such questions, come on back and ask them.
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rollmottle

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Re: Digital tracking with low levels = better...is this new???
« Reply #41 on: January 12, 2007, 04:44:21 pm »

seems to me a sticky at the top of this forum with a guide to digital recording/mixing levels and the reasoning behind it is in order.

would be a great reference if it was all in one place rather than always having to go digging around the forums for the many threads on the subject.

and then when it came up again, everybody could just reply with a link to that thread.  Very Happy
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compasspnt

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Re: Digital tracking with low levels = better...is this new???
« Reply #42 on: January 12, 2007, 05:09:33 pm »

Thanks, rm.

I have actually been considering doing just that, but to do it right is a massive job, somewhat akin to the books I am mired in writing right now.

I will try to put it together though.
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rollmottle

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Re: Digital tracking with low levels = better...is this new???
« Reply #43 on: January 12, 2007, 05:34:27 pm »

compasspnt wrote on Fri, 12 January 2007 14:09

Thanks, rm.

I have actually been considering doing just that, but to do it right is a massive job, somewhat akin to the books I am mired in writing right now.

I will try to put it together though.



totally understandable...and i do appreciate the "do it right" approach - one of my golden rules. i'd offer help if i could. but it's certainly not my area of expertise by any stretch. let me know if i can be of assistance in any way.
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cerberus

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Re: Digital tracking with low levels = better...is this new???
« Reply #44 on: January 12, 2007, 06:18:08 pm »

protools may be a popular choice, but perhaps it isn't state of the art for sonics.  for example: with other daws,  it can be nearly impossible to clip anything internally.

jeff dinces
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