Roon with Fii0 M11 Pro

The Roon app on Fii0’s M11 Pro works (when the unit is connected to Wifi). But I can’t see a signal path nor I can’t use DSP functions, so what is the actual output to the connected earphone?

It’s not FiiO’s problem. It’s an android issue.
Whilst Qobuz, for example, has an app that does work around Andorid’s core sound system, Roon does not. As such, you see the green dot because all files are being routed through the core sound system and missing out some of the FiiO goodies.
Roon are aware of this, it’s just going to take some time before they address the issue.

I really hope they address this soon as I have a iBasso DX160 coming and would like to make use of its internal DAC for Roon as it bypasses all Androids resampliing and can do MQA rendering, which I wont get with Roon in its current state.

My question was more about the precise nature of the data because the music sounds livelier when the same title is read/played from microsd

Yes - that is what I implied: when played from the microsd the files are being fed through all of the FiiO internal DAC electronics/software. When played through via Roon, the path is restricted to the core Android electronics/software.
For this reason, music played from the SD card, or from Qobuz (as it does access all of the FiiO goodies) sounds better.

Thanks Tim, I understand. Also found the signal path on the “now playing page”, slightly other lay-out. When choosing hi-res files they are downsampled…

Yup - it’s a bit frustrating but Roon is intending addressing the issue at some point. The more people raise this as an issue, the sooner this might be addressed. Quite a few Roon users just use Android devices as control units rather than endpoints - they dismiss the sound quality of devices such as the M11. Shame, really.