Post Calibration (Logic & PT)

[guitarflow]

From what I know, the headroom and therefore the output levels you get when you set the fader to a certain level is dependent on the setting of the hardware ( or the Digital-to-Analog Converter to be precise ) used, not on the software.
I remember our technicians set the headroom levels of the old Pro Tools 888 interfaces by adjusting some screws the devices had.

If the hardware has 20 dB of headroom, you will receive 0 dBU at -20 dBFS for example.

QuickTime or iTunes will always play out at a maximum of 0 dBFS if you don't lower the volume slider. And as you surely know : (pop / rock ... ) music tries to be as loud as possible, thus will try to hit the 0 dBFS mark.

Hmm, I don't really have an explanation for the 3 or 4 dB difference.
Although + 3dB would make sense as it is the amount of added output volume when two equally loud signals ( that are not correlated ) are mixed together.

You should maybe try googling "headroom".
Maybe this brings a solution.

Best,

Flo

[markalex]

Sorry everyone -- fixed the PT/Logic discrepancy. Turns out it WAS the pan law settings. (Now both DAWs will work in -3dB NON compensated sessions.

Re: Pink noise -- I naively set Logic's Pink Noise Generator to -20 dB to calibrate, but in order to get an RMS output I needed to crank it to -10dB. All seems reasonable now.

Sorry for the confusion.