Topic: Volume Ref Level setting for digital output - Pro FS.
I have an ADI-2 Pro FS that I use as a desktop headphone amp and digital preamp for a downstream monitor controller (Toslink out from ADI-2). Hats off to RME for making something that (once you figure out how to configure it!) is so seamless to operate in daily use for mixed headphones and monitor usage. The primary input is an AirPlay2 streamer (WiiM Pro) connected via Toslink, though once in a blue moon I'll connect my M1 MBP over USB. I cannot tell a difference in sound quality, only latency (for my pleasure listening application, irrelevant) so usually stick to streaming.
However, I have a question about the Reference Level setting for the digital out. When I set it fixed, there seems to be no difference in output level at a given volume setting. However, if I use Auto Ref Lev there is a step down in level when the ADI-2 "changes gears." Is there any reason to use Auto Ref Lev when using digital outputs from the ADI-2 Pro FS?