I´am using Volumio with a Meridian Explorer (USB) on the RPi. The Meridian Explorer can show with the help of three LEDs which sampling rate the music has.
I have setup Volumio to make an upsampling up to 192kHz (Fastes Sync Interpolar) of my music which goes via AirPlay to the RPi. The Meridian Explorer shows me, that the upsampling does not work, I only see one LED, which indicates 44.1 kHz.
Why would you want to upsample? What do you think to gain?
I understand that there could be situations that you have to feed a DAC a very specific sampling frequency, but besides that, why?
“I will use software volume level control. If my signal has more bits and is upsampled with a decent algorithm, the volume control will have a better data to work with and the final product will be better when I listen at low levels.”
It may be superstition or false reasoning but this is what I believe currently.