Topic: Roon volume vs Auto Ref level

Hi, I just purchased my RME ADI 2 Pro FS BE and started using it in my system with Roon endpoint on Pi4 feeding USB input. After playing with Auto Ref level feature I realized that I cannot take advantage of it because my power amp is a bit overpowered for my small room and max listenable RME volume for me is -22 db which is within +4 Ref level. But I can easily lower input volume level as I'm using Roon volume leveling. With -23LUFS volume level for Roon I can set -16db volume level for RME which uses +13 Ref level. In theory this should not introduce any additional noise as Roon uses 64 bit float processing for volume and converts to 32 bit for dac input.
So my question is what is better for ADI-2 Pro performance - lower digital signal level with +13 ref level or higher signal level with +4 Ref level? I see that +4 Ref level has slightly lower SNR in specs.

2 (edited by ramses 2021-09-19 13:15:51)

Re: Roon volume vs Auto Ref level

If your power amp is too loud then use attenuators, see this thread:
https://forum.rme-audio.de/viewtopic.php?id=25399

These are flexible because they are switchable between 10 dB, -20 dB and -30 dB:
https://www.thomann.de/gb/jts_ma_123.ht … UiOiJlbiJ9

Use such an attenuator to dampen up to 30dB. Then again on the ADI-2 Pro keep auto ref level enabled and turn down the volume as needed. Auto ref automatically chooses the optimum ref level for highest SNR and dynamic range and will also considers B/T and PEQ settings in this calculation.

BR
Ramses
X10SRi-F, E5-1650v4, Win10Pro21H2, Cub11Pro, UFX+, XTC, 12Mic, ADI-2 Pro FS R BE, RayDAT

Re: Roon volume vs Auto Ref level

Thank you. But I’m still wondering is there any disadvantage in attenuating input signal using 64 bit software? I’m trying to understand what is better for ADI 2 - higher digital signal volume or lower

4 (edited by ramses 2021-09-19 13:28:18)

Re: Roon volume vs Auto Ref level

If you reduce the output signal already at the player software, then you reduce the dynamics irretrievably and the signal is already no longer bitperfect in the digital domain before/up to the D/A converter. The best way to reduce the loud power amp is to use an attenuator in the analog domain. The rest you do in the digital domain where auto ref level supports you perfectly to optimize automatically for highest SNR (and thus dynamic).

BR
Ramses
X10SRi-F, E5-1650v4, Win10Pro21H2, Cub11Pro, UFX+, XTC, 12Mic, ADI-2 Pro FS R BE, RayDAT

Re: Roon volume vs Auto Ref level

I'm fine with non bitperfect as I believe that 64 bit processing should not alter dynamic range significantly. I used Roon DSP before for volume leveling at -14LUFS and for room / headphones correction. But I agree that JTS MA-123 is better solution for attenuation as it can also prevent from loud pops / clicks and other things. Going to order a couple of them. Thank you!