How did you do this? I assume line out of the 7xx and into the R09 and then adjust the level until it matched -12? I would think that the 7xx output would add gain but maybe not.
That is exactly how I did it. It doesn't add gain but you can set the level tone to whatever output you want. I did -12 line out of the SD to line in of the R09HR and adjusted the R09HR till it read -12 on its level meter. When that was done I checked -20 and sure enough it read -20 on the R09HR. very cool feature....
well... The lack of math involved here has me worried as to how much benefit you're getting. Maybe you just didn't include that, but I'd check a few things first:
1) What is your 722 set to output on (is there any pad, if not, then the tape out is one value and the mini-xlrs are +20dbu). It's a setting in the menu.
2) What's the max input on the r09hr?
3) What are you setting the tone to (dbfs rating)?
One you get #1 and #3, you can figure out the dbu of the signal as it's leaving the 722, and then once you figure out the max in (which would represent 0dbfs with no gain added). Now, if you already know that the setting of 40 is unity, you can find out what #2 is which is handy in calibrating preamps for maximum output to the recorder (e.g. if a setting of 40 is unity, and you find out that your signal is really +23dbu at that point, then if you preamp only goes to +20dbu before crapping out, add 3db as tested by the 722's tone generator to the r09 so that it clips at the same time as your preamp). It's that last aspect that is particularly handy. That's actually how I found out that the voltage you feed an old sonosax determines where it overloads.