ProTools Reference Level Settings (+10 dBu vs +24 dBu)

[jgiannis]

Hi.

I am running PT10 HD on OSX 10.7.5.

My interface is an AVID HD OMNI.

I use ProTools daily, but what I don't use too often is another piece of software that, I think, came installed with the HD OMNI. The program is called "Avid CoreAudio Manager."

When I open the program, it recognizes the HD OMNI as my interface. (It simply says "Interface: HD OMNI.")

Under the "HW Setup…" button, I click on the tab "Analog Out." I am then given a "Reference Level" for channel 1 through channel 8. Each channel allows me to select either:
(a) Speaker (+10 dBu), or
(b) Line (+24 dBu)

If I set them to +10, then my playback levels are quieter than if I set them to +24. However, the output meters on the OMNI do not change. The output meters give me the same reading, whether I select +10 or +24.

I am not sure which one is "correct," nor do I even understand what this stuff means. But this does affect me because I am currently trying to balance the overall levels of my session. If I am balancing them at +10, then I send my session to another party who has theirs set to +24, their ears will pop off.

Can anyone make sense of this?

Thanks!