Impedance measurement real low desibels with Audient Evo 4?

[Simple Man]

Iam using line out since cant find microphone out setting in rews outputs. There is not so much info on line output, impedance is <100 ohm and level 16dbu. Iam just wondering what is the best value for resistor? Iam now using 200ohms, does it make any difference to db output?

 

[John Mulcahy]

That's a little high but may work, it might make results a little noisier.