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UAPP and Android resampling
Long ago on the Head-fi USB Audio recorder thread someone asked Davy Wentzler a question about playback in USB Audio recorder and Android resampling:
Davy Wentzler said: 
Quote:Good question. Android (usually) has a fixed native sample rate of either 44100 or 48000Hz. Everything else is sample rate converted to this rate (by a worse sample rate converter than used by UAPP). If your Android device has a native sample rate of 44100Hz then you are lucky since if you playback 44100Hz material, the Android sample rate converter (SRC) doesn't need to do anything. When using the variable rate setting, UAPP will feed the sample data as is up to the sample rate that the Android device supports internally (before SRC). It usually has rates up to 96000Hz. So, when playing a 96000Hz file with variable rate setting, 96000Hz audio data is fed to Android and then sample rate converted to either 44100 or 48000Hz by Android. Note that Android's SRC usually causes a (sometimes dramatic) decrease in volume.

So what do we learn from this? Basically, it's best to use the fixed native rate since then UAPP's SRC is used and not Android's (or both).

There are very very few Android devices that actually use a variable sample rate without a fixed sample rate. For those devices, the variable rate setting is best.
I am using UAPP on Onkyo DP-X1, not USB Recorder,  with  the Android sampling rate set in UAPP to variable. 
When I am playing  the 44.1kHz, 48kHz, or 96kHz files, the UAPP shows the same sampling rate for Android and the file. For example "Android:   44100 Hz, file: 44100 Hz.", Android:   96000 Hz, file: 96000 Hz."

Does it mean that when using UAPP on DP-X1,  with variable sample rate, Android on DP-X1 will not resample? DP-X1 uses 5.1.1 version. 
There are a lot of complains about Android resampling and SQ. If UAPP offers the way arouind it, at least on certain devices, that woukld probably excite a lot of folks. 
By the way great app, works on DP-X1, I am using it for everything including Tidal.
UAPP does not have this problem when using its driver and a USB DAC. Whether the Onkyo works without resampling with the 'Android sample rate' option to 'Variable sample rate', depends on Onkyo. Only measuring or asking Onkyo would clear that up.

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