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dBu compare
Old 3 weeks ago
  #1
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dBu compare

+24 , +22 +20 , +18 , + 16 , +14 .... dBu
this is number of more interface for input or output .
cheaper interface number is +14 up to +18 ( mostly )
higher cost and new interface +24 dBu or +22 .
some of sound card like RME is optional to change dBu .

When convert A to D , 0 db VU change to one of this number .
in +14 dbu interface near to 0 dBfs ( peak ) and we can decrease our preamp gain for record . for example :
I record vocal with +40 dB gain in my preamp , after that convert to digital . in +14 interface I see -14 db but in +24 interface I see -24 db and then I might be add +10 db gain in my preamp and so it's add 10 db Signal noise .

So , why +24 dbu sound card is higher cost than +14 dBu ?

or in some changeable sound card , what is best choice for select dBu parameter ?
Old 3 weeks ago
  #2
There's a load of good threads on this subject already e.g. 0 dbfs = +24 dBu or +18 dBu? Preference?

Personally I prefer to use +18dBu for DAW sessions running plug-ins or collabs; I use +22 or 24 for iZ RADAR Studio sessions with balanced outboard gear.
Old 3 weeks ago
  #3
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Quote:
Originally Posted by toofanstudio View Post
[...] So , why +24 dbu sound card is higher cost than +14 dBu ?
Because it is inherently more expensive to build analog circuitry capable of operating with that amount of physical power in the real world:

Changing operating levels in the digital domain is only a matter of crunching numbers...

...But in the physical world (where analog lives) higher audio levels require physical devices that are actually capable of higher amounts of actual physical power (and that costs money).
.
Old 3 weeks ago
  #4
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Quote:
Originally Posted by 12ax7 View Post
Because it is inherently more expensive to build analog circuitry capable of operating with that amount of physical power in the real world:

Changing operating levels in the digital domain is only a matter of crunching numbers...

...But in the physical world (where analog lives) higher audio levels require physical devices that are actually capable of higher amounts of actual physical power (and that costs money).
.
I accept your post.
But ,
This is my question : in optional interface like RME , we can select on of dbu for in or out 14 , 19 , 24 dbu .
Which one is ture good ?!
And
When I select cheap sound card with just +10dbu input , I can minimum gain in our preamp up to +24 dbu higher interface . Then our noise is minimum .
?!?!?!
For example :
I record with a same mic - position- preamp - processor to ( digi design 003 LE ) with protools . My Maximum level is -16 db in protools peak meter , but in ( avid hd interface ) with same mic - position- preamp - processor and DAW is -18 db ( maximum level ) .
I know digidesign 003 LE is cheaper than Avid Hd interface . Also digidesign 003 is +16 dbu and HD audio card is higher and expensive +18 db .
But in meter 2 db LE is louder than HD .
We need to more sound with low gain or what ?!
Old 3 weeks ago
  #5
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You need to learn more. Some meters show bit level peak and others show analogue waveform peak. These are not the same.
Old 3 weeks ago
  #6
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Quote:
Originally Posted by toofanstudio View Post
my question : in optional interface like RME , we can select on of dbu for in or out 14 , 19 , 24 dbu .
Which one is ture good ?!
It's best if you tell people exactly which interfaces you're looking at, and exactly which options you're talking about. The brand name and those numbers by themselves really don't mean anything without that context.

Quote:
Originally Posted by toofanstudio View Post
For example :
I record with a same mic - position- preamp - processor to ( digi design 003 LE ) with protools . My Maximum level is -16 db in protools peak meter , but in ( avid hd interface ) with same mic - position- preamp - processor and DAW is -18 db ( maximum level ) .
I know digidesign 003 LE is cheaper than Avid Hd interface . Also digidesign 003 is +16 dbu and HD audio card is higher and expensive +18 db .
But in meter 2 db LE is louder than HD .
We need to more sound with low gain or what ?!
The numbers are confusing. You always have to keep track of what they refer to. We're almost always talking about something in relation to something else. It might seem like louder is better, but really what it looks like (to me) is that the HD card has an extra 2dB of headroom before distortion.

If you think about it top-to-bottom instead it might make more sense. Digital has a peak of 0dBFS. If the interface says +18dB I'm guessing it's talking about the headroom. So 0 (dBFS) minus 18 (dB headroom) = -18dBFS.

Since we can't go beyond 0dBFS in digital our adjustments have to go down as the headroom goes up.
Old 3 weeks ago
  #7
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Quote:
Originally Posted by toofanstudio View Post
This is my question : in optional interface like RME , we can select on of dbu for in or out 14 , 19 , 24 dbu .
Which one is ture good ?!
It depends on what you’re connecting to. For example, if you connect the RME out to a +14 dBu max input, it would make no sense to choose +24, because you would clip too easily. If the opposite and you chose 14 going into 24, you’d never clip, but also leave 10 dB of system headroom basically wasted.

Quote:
Originally Posted by toofanstudio View Post
And
When I select cheap sound card with just +10dbu input , I can minimum gain in our preamp up to +24 dbu higher interface . Then our noise is minimum .
?!?!?!
For example :
I record with a same mic - position- preamp - processor to ( digi design 003 LE ) with protools . My Maximum level is -16 db in protools peak meter , but in ( avid hd interface ) with same mic - position- preamp - processor and DAW is -18 db ( maximum level ) .
I know digidesign 003 LE is cheaper than Avid Hd interface . Also digidesign 003 is +16 dbu and HD audio card is higher and expensive +18 db .
But in meter 2 db LE is louder than HD .
We need to more sound with low gain or what ?!
Try the opposite example: plug a +17 dBu signal into the LE. You won’t like the sound. ; )

The noise floor of pro analog gear is around -80 dBu.

Higher output levels mean better S/N because you are further from -80.

Simple as that.
Old 3 weeks ago
  #8
This [PDF] may answer your questions about levels. I made this up about 20 years ago for my assistant engineers. The default dBFS for most interfaces is -18dBFS = 0VU = +4dBu = 1.228 Vac

At our studio I had all the multitracks aligned for -16dBFS, all the 2 track mixdown recorders set for -12dBFS=0VU.

Good day
Ron Obvious
Attached Files
File Type: pdf dB References.pdf (474.4 KB, 31 views)
Old 3 weeks ago
  #9
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it's not about 'comparing dBu', it's about level matching of gear in the analog domain! i'm still amazed how often this gets neglected even in 'pro' studios... - in live sound, things can get catastrophic!
Old 2 weeks ago
  #10
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https://ibb.co/cL981H9

would you please to see this picture and answer to my question
______
In this pic HD avid calibrated at -18 dbfs and 003 calibrated to -16 dbfs .
So , 003 volum is 2 dB louder than HD avid.
_____
So , we can decrease preamp gain 2 db for -16 calibrated sound card and decrease 2 db noise . My theory is true or false ?
Old 2 weeks ago
  #11
Gear Guru
 

Quote:
Originally Posted by toofanstudio View Post
https://ibb.co/cL981H9

would you please to see this picture and answer to my question
______
In this pic HD avid calibrated at -18 dbfs and 003 calibrated to -16 dbfs .
So , 003 volum is 2 dB louder than HD avid.
_____
So , we can decrease preamp gain 2 db for -16 calibrated sound card and decrease 2 db noise . My theory is true or false ?
Partially true. If you lower your preamp gain then surely some noise will decrease. This will be true for all preamps. You do of course have other parts in your signal chain that create noise so that other noise might not decrease.
Old 2 weeks ago
  #12
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Quote:
Originally Posted by mattiasnyc View Post
Partially true. If you lower your preamp gain then surely some noise will decrease. This will be true for all preamps. You do of course have other parts in your signal chain that create noise so that other noise might not decrease.
Which noise , that I might not decrease ?!
Old 2 weeks ago
  #13
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Quote:
Originally Posted by Ron Obvious View Post
This [PDF] may answer your questions about levels. I made this up about 20 years ago for my assistant engineers. The default dBFS for most interfaces is -18dBFS = 0VU = +4dBu = 1.228 Vac

At our studio I had all the multitracks aligned for -16dBFS, all the 2 track mixdown recorders set for -12dBFS=0VU.

Good day
Ron Obvious
It’s meter matching .
But I answer about low noise low gain , and .... !!!
Old 1 week ago
  #14
Hello toofanstudio.

from the ?screen shot? Ok HD in this case is aligned for -18dBFS=0VU. The D003 (which I actually have right beside me) is aligned to 16dBFS = 0VU.

The output volume is THE SAME!. I.E. 0VU=4dBu output to your amplifier.

Yes on the 003 you are recording the signal 2dB louder in [dig land]. Or the other way to look at it is, with 2dB less digital headroom before 100% digital clipping [not a nice sound at all].

As far as noise floor is concerned. In 24bit land, it's WAY DOWN THERE, at about -115dBFS. This is lower than the very best analog gear there is. (see my earlier PDF) I.E. the noise of your analog recording gear, will be louder than the 24 bit digital noise floor. Of course analog tape doesn't even come close to this.

As mentioned in my earlier post I aligned all the multi-track HD systems in our studio to -16dBFS. This allowed the VU meters on the Neve and SSL's to act better, to the signal without pinning all the time. Note: most consoles only have about 3dB more headroom before they go into complete distortion, anyway. Again shown on the PDF.

Lastly, most analog gear uses +/-15 DC voltage rails. This only allows for about MAX +21dBu bal, before clipping. Only totally pro gear runs with +/-18Vdc (e.g. SSL 4K) about +24dBu. Recently some of the new Rupert Neve gear, etc. use +/- 36 volt rails! Yes old style Neve used single rail +24Vdc, clipping at about +26dBu.

Last edited by Ron Obvious; 1 week ago at 10:16 PM..
Old 1 week ago
  #15
Gear Guru
 

Quote:
Originally Posted by toofanstudio View Post
Which noise , that I might not decrease ?!
Your devices that are analog will generate some noise. What I meant was that if you turn down your preamp then some noise will be lowered, basically any noise that is directly related to that. But other parts of your preamp or other parts of your signal chain will still have some self-noise and turning down the preamp doesn't change that.

It seems to me that the difference you're looking at is so small that there really is no reason for you to adjust the level in order to have less noise. Set the level so that the average is at the nominal/"best" operating level, and lower it if you need more distance from clipping. It doesn't have to be more complicated than that.
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