Chromebook and OpenSL ES Hi-Res Settings

[crowder]

Equipment:

• Acer Chromebook CB515-1HT-P39B (in developer mode)
• FiiO Q1 Mark II DAC
• Sennheiser PXC-550 Headphones (wired)

I have set up the Output as such:

 

However, when I try to use the USB DAC, it is giving me this:

So I've attempted to turn off the speaker in the OpenSL ES Settings, but it won't allow me to keep it turned off. It automatically turns back on.

I'm making the assumption that there is not much that I can do to address this, but I wanted to reach out before setting out on a different course.

Thanks much.