another quick calibration question

[vudoo]

Before everyone shouts at me...yes i did read through the Cal post but i just need to double check something.

I want to calibrate my 192 I/O : A-trim to -18dbfs and B-trim to -20dbfs

- i used the Sign gen and sent 1Khz@-18dbfs to each ouput and trim the A-trim to 1.228 volts
- then sent 1Khz@-20dbfs to each ouput and trim B-trim to 1.228 volts

Is this correct ?? What i'm not sure is even though i change the level from -18 to -20 do voltage adjustment stays the same ( 1,228 volts ) ??



Thanks

[Postman]

Not sure what you're really trying to accomplish so it is hard to answer. That would be one way to do it, if you are using the analog ins and outs exclusively. Obviously, nothing that is passed along digitally will be affected by the analog output trims on your 192io. InTheBox metering will not be affected, for instance. It is not possible for me to say whether it is the best thing for you to do. Maybe if you need to meter and monitor exclusively from the analog outputs (and work with -18 or -20 standards on different jobs) and then layback to video or files using the digital levels that are at their respective levels, okay.

[vudoo]

well, basically i just want to calibrate my 192 I/O Trim-A to -18 dbFS and Trim-B to - 20 dbFS.

This is what i did :

-18 dbFS = 0 VU, + 4 dBu adjust trimA til RMS multimeter reads 1,228 volts
-20 dbFS = 0 VU, + 4 dBu adjust trimB til RMS multimeter reads 1,228 volts


the part i'm unsure is does the 1,228 volts reading stay the same even though i change the 1Khz sine tone from -18 db to -20 db

[danijel]

Vudoo, perhaps I am missing the obvious, but why do you want the double calibration thing? Where are you located? Do you have outboard meters that require different cal than your monitoring?
North American standard (SMPTE RP155): -20dBFS = +4dBu = 1.228V RMS
European standard (EBU R68): -18db dBFS = 0dbu = 0.775V RMS

Check the REFERENCE LEVEL part in my sticky @ Gearslutz:
http://www.gearslutz.com/board/post-...cials-etc.html
And especially the documents that are linked from there.

Best regards!

[vudoo]

when i'm mixing music, i use output trim A ( - 18 dbFS ) and when doing post, i use output trim B ( - 20 dbFS ).
I've been working this way since i got the 192. I have no real reason for doing this other than it works and i'm getting good results, maybe i should not bother and always work at -20 dbFS. Anyways, I'm not technicly inclined at all, thank god, i have you guys around
Thanks again for helping.