@JohnPM
Let's see if John can settle the score.
First, the set-up:
1) Akitika 1 kHz oscillator as the source, connected to the amplifier using a single RCA cable. The other amplifier input is shorted.
2) A cable from the amplifier output to the 3-pin XLR input 1 of a Scarlett 2i2 audio interface.
There is no volume knob leading into the amplifier.
There are 3 knobs on the 2i2: 1) A big knob marked "Monitor", 2) a gain knob for input 1, 3) and a gain knob for input 2.
I calibrated the audio interface in REW and the preferences pane looks as follows:
During the calibration process, I had to turn up the "Monitor" knob so that input level would match output level, as indicated by the Out/In gauges.
Does that mean the "Monitor" knob should be left at the same position for the calibration to remain valid?
Now, in the RTA window,
Should there be an extra calibration in place for the input?
and
Should I uncheck "Get fundamental from generator"? Since the Akitika oscillator generates the signal instead of the REW generator?
Should "Ref resistance" be adjusted to match the value of the dummy load?
Finally, here, how to use this "FS sine Vrms" and the associated "Calibrate level" button, when the source of the signal is the Akitika oscillator?