I am using the  RME ADI-2 pro FS R Be. It is connected to the digital input of the Genelec speaker with AES output. RME ADI-2 pro is set to "DAC mode", and I am using the volume and B/T function well. It makes a good sound and is convenient.

Suddenly, I had a question, so I decided to test it. What I am curious about is what is the bit depth of the AES output. So, I connected the AES output of RME to the AES input.

And I played a 44.1 kHz 16 bit song through optical input, The AES input showed a 44.1 kHz 24-bit indication.

It's a surprise, so I thought about why.

There was a menu called "Dig. Out Source" in SETUP, and I set it to "Main Out." I looked up the manual and found that if I set "Dig. Out Source" to "Main Out," the processed signal goes out. When I changed "Dig. Out Source" to "default," it showed 44.1kHz 16bit as expected.

My guess is that 24 bits were displayed because of the signaling process.

Does this mean that the built-in DSP processes the 16-bit signal after converting it to 24 bits? I'm curious about that. If so, the volume or EQ takes place in a 24-bit domain, which is a good thing.
I hope you guys can check and confirm this.