I don’t notice any difference tbh except now I have it at -30db for the volume I used to have at -40 or -43db
I should keep it at -30db and then just adjust volume with windows?
Cause the windows slider has nothing to do with the volume in the interface.
Before I had interface volume at -42db and the window slider was always around 25-30 depending
Now window volume slider is more like 40-50
Yes, is more or less that, by this way you have also less harmonic distortion and noise, so your setup has globally better SINAD.
The digital volume is better at higher levels, to avoid loosing bit depth (although this is partially avoided by upsampling in the DAC section of your audio interface).
The basis of all this things can be strong but its effects not very audible.
The signal carries noise, mainly unavoidable when quantizing the recording by the AD in your interface (+/- 1 bit), some other from the circuits themselves (a little bit as I remember, mostly is quantization noise and associated harmonic distortion).
Amplification of a weak signal carries more error than amplification of a strong signal. Your audio interface produces a clean 4 volts signal with very low distortion, in general. Not the same as the amplifier, because of operating at higher currents.
This depends on the quality of components but in general is way more easy to produce low distortion and noise at signal levels, in the low current region, so reducing the speakers gain ratio (output / input) and keeping your interface closer to its max is better than the opposite.
Total volume is not affected if you always maintain the (potential) 104 dB SPL of the speakers, reducing signal and multiplying amplification will give same number than increasing signal and reducing amplification: this is a linear property.
Here you will read many times the word “nonlinear” and “nonlinearities” which are properties that change with the operation ratios. Noise and distortion are examples of nonlinearities and the final number of them depends on the operations you’ve done, even if the total volume is the same.