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Posted by: Jeremy Teeters Jan 28 2014, 01:24 AM

Hello,

I was wondering if anyone here might know a procedure for calibrating levels. (i.e.)...My master fader in protools is saying that my digital DBFS is -20, so I know that if my DBFS is -20 then I have 20db of headroom before the signal clips. However, while my master fader reads -20DBFS, my MOTU interface is telling me that the level is -6PPM or so @ half volume on the headphone amp & mains. If I turn the volume up or down on the MOTU the levels also are raised up or down on the meters from the MOTU. The levels on the master fader in protools stay constant as they should. So if protools is DBFS digital signal and my MOTU is PPM how do I calibrate the PPM level to match the DBFS signal? Any help or professional advice would be very appreciated.

Sincerely,
Jeremy

Posted by: Jeremy Teeters Jan 28 2014, 06:16 PM

lol, I figured as much.

Posted by: Nick Jan 31 2014, 01:09 PM

Hello Jeremy,

It all depends if you have an access to adjust the levels on the interface, years ago there were quite a few interfaces that let you physically adjust the levels by taking a screwdriver and turning the pots.

You might be able to do this through the software associated with the interface.

In any case you will have to send a sine wave that is at your reference level of -20 from your DAW and then adjust to match on your interface.

But as the scale on various equipment are relative and a bit arbitrary, the simplest way would be to mark with china graph pencil where the levels are on the interface where your signal is at that -20DBFS coming out. Else you might risk overloading or underexploiting the convertors on the interface.

My 2 cents.

Best Regards,

Nick