If needed, there are calibration pots for the VU meters inside their compartment - pop the front glass piece (gently pull out the tape monitor selector button and slide the glass out). You will see the trims...
Calibrating the meters is difficult, because you need to know a number of variables --
a) the exact level of the signal you're feeding in (test tone from a CD or signal generator)
b) the exact output level of the device that is generating the tone
c) the exact delta between a reading off the peak meters and the reading off the VU meters. (Mackie says they can be 3-4 db apart - which isn't an accurate enough spec for calibration!)
You can easily adjust if one meter doesn't quite read the same as the other by simply feeding a 1khz tone to the board and using the meter trims on one of the meters to have them read the same.
Now - as to levels.... you have to know where the 0db mark has been calibrated on the recorder....
I have no idea about your reel-to-reel - the manual may tell you, but for the ADAT.... a 0db 1khz tone on the board, using the +4dbU gain structure on both the recorder and the board, will give you a -15db reading on the ADAT meters.
(-15db is the calibration point for a 0db reading on a console, for both -10 or -4 gain structures) This gives you basically 15db of headroom before a digital over (although the actual amount is probably 16db, since the digital over usually shows before any actual distortion is heard)
Hope this helps......
Bruce
