Proper Calibration Process for Analog/Digital signal chain

[Vocalpoint]

All,

Been a huge fan of the forum and the UAD-1 for a while now but have been seriously wondering if I really have my gear gain-staging calibrated properly across my entire signal chain (minus the monitors for now).

Currently I am running a Delta 1010 into a Soundcraft Spirit M12 and have Nuendo 3.x as my DAW. I have searched high and low and really have not been able to get a totally clear picture on what the actual correct steps are for ensuring the calibration is correct.

Here's what I have so far (which may or may not be correct):

1. I downloaded the standard -20dbFS pink noise file from a source on the net.
2. Load that up in Nuendo and run it...
3. With the Nuendo master bus fader at 0 - my Nuendo meters read -20dbFS
4. Move master M12 outputs to untiy (0db) and adjust input fader on the M12 strip (that contains the Delta 1010 signal) so the master output meters on the M12 read 0VU

FWIW - all my connections from the Delta are set to 4dbU....

Am I on the right track? Do I need to run the pink noise thru every channel on M12 to get the right gain stage? How about tracking into Nuendo - if I calibrate all channels to 0db on the Soundcraft - is it as simple as adjusting the input trim when recording a track so the M12 master outpur is peaking at 0db and subsquently being recorded at -20dbFS/-19dbFS? in Nuendo?

Or am I missing something?

Any help would be most appreciated!

Cheers!

 

[MASSIVE Mastering]

If the \"meat\" of the signal on the board is reading around 0dBVU, the \"meat\" of the signal in Nuendo should read around -20dBFS. Most likely, it will peak considerably higher - Perhaps -12, occasionally -10 or so. But it should \"hover\" around -20dBFS.

The only signal you have to worry about is the signal at the preamp you're using at the time - Everything else at unity, all should work as designed.

 

[Vocalpoint]

John,

Thanks for the update. However - I have discovered a few more anomolies which make little sense to me.

For starters - my calibration files are from here:

http://www.abluesky.com/p_s_gb/p5s10.html

1. 1000Hz SINEWAVE -20dBFS.wav – a 1kHz file recorded at -20dBFS for electrical calibration
2. 40-80Hz PINK NOISE -20dBFS.wav – a 40Hz to 80Hz bandwidth limited pink-noise file recorded at -20dBFS
3. 500-2.5kHz PINK NOISE -20dBFS.wav - a 500Hz to 2500Hz bandwidth limited pink-noise file recorded at -20dBFS
4. Pink Noise full bw -20dBFS.wav – a full-bandwidth pink-noise file recorded at - 20dBFS

When I started to calibrate last night - I used File #1. Whn I played this back in Wavelab (it played back at exactly -20dBFS...but in Nuendo - this same file plays back at -23dbFS. Is my metering wrong in Nuendo? Why the difference?

Also - when I used File 1 and attempted to use it to set my Soundcraft correctly...I did the following:

1. Started File #1 playback in Wavelab.
2. Make sure my master faders on the Soundcraft were at 0db
3. Made sure the channel strip that was taking the output from the Delta 1010 was at 0dB.
4. Adjusted the input trim on that channel to ensure the master output bus on the Soundcraft read exactly 0dB as File #1 was being played back.

While it was easy enough to do - I found that the input trim on the Soundcraft (carrying the Delta 1010 output) had to be adjusted well beyond it's 0db marking on the knob itself to ensure the master outputs read 0db. At first I didn't think much of it....but upon playback...this gain was huge.....

Then I slept on it and tried again this morning....this time using File #4...Playback of this file thru Wavelab actually reads -11.4dBFS (or thereabouts) when loaded. Oddly when repeating the exact steps above using this file - the input trim knob setting on the Soundcraft M12 carrying the Delta 1010 output now sits exactly at 0 resulting in a perfect 0db on the M12 master faders.

So - what file is correct? Why do all these files indicate that they are recorded at -20dBFS but they are all over the map when played thru my gear? Do I use File 1 as the gospel or File 4? For another angle - I also got hold of Bob Katz's standard pink noise file and it too reads somewhere around -12dbFS....so it's obvious that my correct Delta 1010 calibration point is not 0db = -20dBFS....it's more like 0db = -12dBFS....

Help?