Sound About setting for Tablet

I have an Acer 500 tablet running a custom ROM with 5.1.1, that I do not use for anything but music/media out of the USB ONLY.
 That means no phone, no messaging and no alerts or notifications that relate to those functions.

I need to know what are the best settings are for my tablet and for Sound About to make this work consistently.  
Right now, it will play out the speakers but will not play out the USB host setting. It seems to work sometimes and other times not.

 I have tried both setting it to "USB Host only" as well as "Let app decide" on and have set it to ignore headset plug

Thanks!

So it does play audio from the USB sometimes?

I'm surprised that tablet does that, even with 5.1.1.

I would think that you may need an OTG cable.

https://www.androidpit.com/usb-otg-what-it-means-and-how-to-use-it

More information here:
http://www.extreamsd.com/index.php/2015-07-22-12-01-14/usb-audio-driver

I have UAPP works every time if I play native files but SA works only sometimes when I try to stream music.
My original question was what settings should i use in SA and on my tablet to use it as a dedicated media player.
No phone, no notifications no alarms etc.

Did you set the Media Audio setting to USB Host? That only opens the channel for file sharing. It looks like UAPP developed a dedicated USB driver.

http://www.head-fi.org/t/704065/usb-audio-recorder-pro-uapp-24-and-32-bit-playback-ubiquitous-usb-audio-support-for-android