Interesting... I never knew that. I wonder if the Mobius compensates for this with the built in EQ profiles.
I've measured it (for Music EQ), and yes, the EQ curves are identical in "7.1" and "High Res".
Higher sample rates don't improve low level resolution by much, but higher DAC bitrate can, in case the volume is lowered digitally.
With 24bit you can go 48dB down digitally and still have 16bit resolution - but no longer full 16bit Signal to Noise Ratio (SNR), because usually 24bit converters are only about 12 to 24dB (not 48dB) better in noise floor then 16bit converters.
When using digital volume control (like in Mobius and almost every current production digital device) the absolute noise floor is constant - you either hear it or not, independent of volume setting.
That's what caused Mobius initial noise problems, Audeze choose a too high analog amplifier's post-gain after the DAC, so DAC residual noise became audible to a majority of people.
Now the analog stage hardware gain is lowered, on cost of max. achievable soundlevel.
There are no complaints that Mobius isn't loud enough if feed from digital sources that feed unchanged signals.
There are some complaints if Mobius analog Aux-input is used from weak sources.
It takes 1.8V for driving Mobius Aux In's ADC fullscale - the level that usually comes out of desktop CD players.
@Kman Audeze should incorparate some amount of digital post gain into the volume control when the Aux connection is used, to deal with weaker sources.