UAPP and modern USB-C 3.1 smartphone, docking station, multiple DACs

[earlgrey]

Hello community,

I would like to discuss and bring to your attention the following development:

For many years, the audiophile smartphone universe was based on USB 2.0 (OTG), with simple choices:
-> charge your phone, but don't listen to your external DAC, or
-> listen to your external DAC, but you can't charge your phone at the same tine
  (and in a non-portable setup you will run out of battery soon)

For more then TEN YEARS (literally!) I have been waiting for a solution to this problem (because I use Android phones exclusively as audio players, in stationary, non-portable setups). The wait is finally over!

Latest smartphones feature USB-C 3.1 support, very much like recent laptops:
-> connect a USB-C 3.1 docking station
-> charge the phone (rapidly!)
-> connect and use your external DAC at the same time
-> connect an SSD with your music
-> even utilize the docking station's Ethernet port
  (no Wifi connection for the phone required)

Isn't this a fantastic development? Well almost, I can now listen to music while the phone is charging, but the struggle continues. Here is why...

So I am using my brand new smartphone and connect to a Dell WD15 (because I have a few of those as spare).

Code:

Here is what I expected:

                    Power
                      |
| ---------|    | ---------|    | ---------|
| Phone    | -> | Dock     | -> | DAC      |
| ---------|    | ---------|    | ---------|


But this is what I got:

                    Power
                      |
| ---------|    | ---------|    | ---------|
| Phone    | -> | Dock     | -> | DAC      |
| ---------|    |          |    | ---------|
                |          |
                | internal |    | ---------|
                | audio    | -> | headset  |
                | ---------|    | ---------|

And now I am playing round-robin-catch-me-if-you-can with UAPP: Sometimes it opens the external DAC, and sometimes it opens the Dock's headset output (which is named "USB audio" at 48kHz). So this gets very annoying at times.


And the ideal audiophile smartphone universe would look like this:

                    Power
                      |
| ---------|    | ---------|    | ---------|
| Phone    | -> | Dock     | -> | DAC 1    |
| ---------|    |          |    | ---------|
                |          |
                |          |    | ---------|
                |          | -> | DAC 2    |
                |          |    | ---------|
                |          |
                | internal |    | ---------|
                | audio    | -> | headset  |
                | ---------|    | ---------|

SO HERE COMES MY FEATURE REQUEST
UAPP should detect multiple / all connected USB outputs and support the selection of the desired output, and it should do away with the "Play through Android" setting completely. Instead, UAPP should simply enumerate all attached USB DACs (including the dock's USB audio, and including the Android standard output), in the form of a dropdown widget, and remember the last used, like in the attached picture.

What do you think? This would address
a) the issue with docking stations containing their own USB audio interface, and
b) I am sure that many audiophiles would love to switch & compare DACs at their disposal.


Best Regards,
Lars

[earlgrey]

If there is no interest from the community, may I ask the developer to at least implement a setting where I can exclude the unwanted DAC by name? I can also offer to ship a Dell WD15 to you for testing, as I have plenty of those.

[dwrae]

User interface-wise that would be quite some effort for something that is rarely needed. We used to have a config/text file for that, but nowadays, apps cannot read files anymore from any directory. We need to give this some more thought.

[Maverick565]

I wish to have this feature too. I have plans to buy similar usb-c dock for my S20 FE to not drain battery when playing music. 99% of music i plays with smartphone with usb dac. But I'm afraid of degrading the sound quality.