I have the same issue with the android sabre dac and Lenovo P-70 (on Lollipop).
The sound volume is very low and and quality is worse than the regular headphone output, when using any generic player - Spotify or Built In Music Player. The dynamic is also very bad at less than 80% volume.
Also it seems the music is being played in both DAC and Headphone output.
I tried this player https://play.google.com/store/apps/details?id=com.hiby.music&hl=en and also tried trial USB audio player pro and the resuld is very much completely different.
Both get access to the USB device and play exclusively through the dac. The volume is enough even and 45%.
As far as i researched i also found that the USB hub does support hardware volume control, but it does not seem to work with USB audio player. Control is shown in the app but it does nothing. So it implements some "software" volume.
Could you please ellaborate on these issues and tell more about the volume control implementation since it seems the PCM2706 chip do support volume control, and it is detected by the player but it does not seem to do nothing.
Best Regards, Chavdar
It seems from your experience that your phones with Cyanogenmod doesn't work correctly with the DAC. It is difficult to test and support all phones/software versions. in our tests Cyanogenmod did not work at all, while Samsung's Android versions normally works. You can try to update or change the kernel which might solve it, as the DAC function relies on the kernel.
Yes, USB audio player pro uses it's own drivers which explains why it behaves differently.
The volume control on USB level is not supported by PCM2706. However on most Android phones the volume up/down buttons works to adjust the USB DAC volume. So it means that Android is doing this in software.
Sorry that we don't have a better solution for this issue other than to recommend you try to update/change the OS software or kernel.