I added an Excel Sheet with an overview of Volume, Reference Levels, SNR and Auto Ref Level ranges to the sticky posting about the different models of Reference Converters (ADI-2 DAC/PRO, ADI-2/4 Pro SE) to have this at one place.

https://forum.rme-audio.de/viewtopic.ph … 06#p165706

There you can see e.g. the effect of Auto Ref Level, how far you can turn the volume down and still have nice SNR/Dynamic.

Here a summary for the 3 reference converter (ADI-2 DAC FS has additional values for the RCA output) up to which volume decrease you still have a good SNR which is equal (not worse) compared to the lowest value of the 2nd last ref level.

• ADI-2/4 Pro SE:         Lowest SNR 114.5 at lowest volume setting -27.5

• ADI-2 Pro FS R BE:    Lowest SNR 111.5 at lowest volume setting -27.5

• ADI-2 DAC FS (XLR): Lowest SNR: 114.5 at lowest volume setting -20.5

• ADI-2 DAC FS (RCA): Lowest SNR: 110.5 at lowest volume setting -19.5

Or in other words, to still achieve a SNR/Dynamic of 110 dB you can turn the volume down to:
[*]ADI-2/4 Pro SE:         -32[/*]
[*]ADI-2 Pro FS R BE:    -29[/*]
[*]ADI-2 DAC FS (XLR):  -25[/*]
[*]ADI-2 DAC FS (RCA): -20[/*]

The max dynamic range of a music CD is 96 dB. To still reach 96 dB SNR/dynamic you can turn the volume down to:
[*]ADI-2/4 Pro SE:         -46[/*]
[*]ADI-2 Pro FS R BE:    -43[/*]
[*]ADI-2 DAC FS (XLR):  -39[/*]
[*]ADI-2 DAC FS (RCA): -34[/*]

Additionally, some calculations regarding Volume and respective dBu, dBV and Volt (eff).